brintos / linux-shallow public Read only

1// SPDX-License-Identifier: GPL-2.02/*3 * Shared application/kernel submission and completion ring pairs, for4 * supporting fast/efficient IO.5 *6 * A note on the read/write ordering memory barriers that are matched between7 * the application and kernel side.8 *9 * After the application reads the CQ ring tail, it must use an10 * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses11 * before writing the tail (using smp_load_acquire to read the tail will12 * do). It also needs a smp_mb() before updating CQ head (ordering the13 * entry load(s) with the head store), pairing with an implicit barrier14 * through a control-dependency in io_get_cqe (smp_store_release to15 * store head will do). Failure to do so could lead to reading invalid16 * CQ entries.17 *18 * Likewise, the application must use an appropriate smp_wmb() before19 * writing the SQ tail (ordering SQ entry stores with the tail store),20 * which pairs with smp_load_acquire in io_get_sqring (smp_store_release21 * to store the tail will do). And it needs a barrier ordering the SQ22 * head load before writing new SQ entries (smp_load_acquire to read23 * head will do).24 *25 * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application26 * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*27 * updating the SQ tail; a full memory barrier smp_mb() is needed28 * between.29 *30 * Also see the examples in the liburing library:31 *32 *	git://git.kernel.dk/liburing33 *34 * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens35 * from data shared between the kernel and application. This is done both36 * for ordering purposes, but also to ensure that once a value is loaded from37 * data that the application could potentially modify, it remains stable.38 *39 * Copyright (C) 2018-2019 Jens Axboe40 * Copyright (c) 2018-2019 Christoph Hellwig41 */42#include <linux/kernel.h>43#include <linux/init.h>44#include <linux/errno.h>45#include <linux/syscalls.h>46#include <net/compat.h>47#include <linux/refcount.h>48#include <linux/uio.h>49#include <linux/bits.h>50 51#include <linux/sched/signal.h>52#include <linux/fs.h>53#include <linux/file.h>54#include <linux/fdtable.h>55#include <linux/mm.h>56#include <linux/mman.h>57#include <linux/percpu.h>58#include <linux/slab.h>59#include <linux/bvec.h>60#include <linux/net.h>61#include <net/sock.h>62#include <linux/anon_inodes.h>63#include <linux/sched/mm.h>64#include <linux/uaccess.h>65#include <linux/nospec.h>66#include <linux/fsnotify.h>67#include <linux/fadvise.h>68#include <linux/task_work.h>69#include <linux/io_uring.h>70#include <linux/io_uring/cmd.h>71#include <linux/audit.h>72#include <linux/security.h>73#include <asm/shmparam.h>74 75#define CREATE_TRACE_POINTS76#include <trace/events/io_uring.h>77 78#include <uapi/linux/io_uring.h>79 80#include "io-wq.h"81 82#include "io_uring.h"83#include "opdef.h"84#include "refs.h"85#include "tctx.h"86#include "register.h"87#include "sqpoll.h"88#include "fdinfo.h"89#include "kbuf.h"90#include "rsrc.h"91#include "cancel.h"92#include "net.h"93#include "notif.h"94#include "waitid.h"95#include "futex.h"96#include "napi.h"97#include "uring_cmd.h"98#include "msg_ring.h"99#include "memmap.h"100 101#include "timeout.h"102#include "poll.h"103#include "rw.h"104#include "alloc_cache.h"105#include "eventfd.h"106 107#define IORING_MAX_ENTRIES	32768108#define IORING_MAX_CQ_ENTRIES	(2 * IORING_MAX_ENTRIES)109 110#define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \111			  IOSQE_IO_HARDLINK | IOSQE_ASYNC)112 113#define SQE_VALID_FLAGS	(SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \114			IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS)115 116#define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \117				REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \118				REQ_F_ASYNC_DATA)119 120#define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\121				 IO_REQ_CLEAN_FLAGS)122 123#define IO_TCTX_REFS_CACHE_NR	(1U << 10)124 125#define IO_COMPL_BATCH			32126#define IO_REQ_ALLOC_BATCH		8127 128struct io_defer_entry {129	struct list_head	list;130	struct io_kiocb		*req;131	u32			seq;132};133 134/* requests with any of those set should undergo io_disarm_next() */135#define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)136#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)137 138/*139 * No waiters. It's larger than any valid value of the tw counter140 * so that tests against ->cq_wait_nr would fail and skip wake_up().141 */142#define IO_CQ_WAKE_INIT		(-1U)143/* Forced wake up if there is a waiter regardless of ->cq_wait_nr */144#define IO_CQ_WAKE_FORCE	(IO_CQ_WAKE_INIT >> 1)145 146static bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,147					 struct task_struct *task,148					 bool cancel_all);149 150static HWJS_SUSPENDS void io_queue_sqe(struct io_kiocb *req);151 152struct kmem_cache *req_cachep;153static struct workqueue_struct *iou_wq __ro_after_init;154 155static int __read_mostly sysctl_io_uring_disabled;156static int __read_mostly sysctl_io_uring_group = -1;157 158#ifdef CONFIG_SYSCTL159static struct ctl_table kernel_io_uring_disabled_table[] = {160	{161		.procname	= "io_uring_disabled",162		.data		= &sysctl_io_uring_disabled,163		.maxlen		= sizeof(sysctl_io_uring_disabled),164		.mode		= 0644,165		.proc_handler	= proc_dointvec_minmax,166		.extra1		= SYSCTL_ZERO,167		.extra2		= SYSCTL_TWO,168	},169	{170		.procname	= "io_uring_group",171		.data		= &sysctl_io_uring_group,172		.maxlen		= sizeof(gid_t),173		.mode		= 0644,174		.proc_handler	= proc_dointvec,175	},176};177#endif178 179static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)180{181	return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);182}183 184static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx)185{186	return READ_ONCE(ctx->rings->cq.tail) - READ_ONCE(ctx->rings->cq.head);187}188 189static bool io_match_linked(struct io_kiocb *head)190{191	struct io_kiocb *req;192 193	io_for_each_link(req, head) {194		if (req->flags & REQ_F_INFLIGHT)195			return true;196	}197	return false;198}199 200/*201 * As io_match_task() but protected against racing with linked timeouts.202 * User must not hold timeout_lock.203 */204bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,205			bool cancel_all)206{207	bool matched;208 209	if (task && head->task != task)210		return false;211	if (cancel_all)212		return true;213 214	if (head->flags & REQ_F_LINK_TIMEOUT) {215		struct io_ring_ctx *ctx = head->ctx;216 217		/* protect against races with linked timeouts */218		spin_lock_irq(&ctx->timeout_lock);219		matched = io_match_linked(head);220		spin_unlock_irq(&ctx->timeout_lock);221	} else {222		matched = io_match_linked(head);223	}224	return matched;225}226 227static inline void req_fail_link_node(struct io_kiocb *req, int res)228{229	req_set_fail(req);230	io_req_set_res(req, res, 0);231}232 233static inline void io_req_add_to_cache(struct io_kiocb *req, struct io_ring_ctx *ctx)234{235	wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list);236}237 238static HWJS_SUSPENDS __cold void io_ring_ctx_ref_free(struct percpu_ref *ref)239{240	struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);241 242	complete(&ctx->ref_comp);243}244 245static HWJS_SUSPENDS __cold void io_fallback_req_func(struct work_struct *work)246{247	struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,248						fallback_work.work);249	struct llist_node *node = llist_del_all(&ctx->fallback_llist);250	struct io_kiocb *req, *tmp;251	struct io_tw_state ts = {};252 253	percpu_ref_get(&ctx->refs);254	mutex_lock(&ctx->uring_lock);255	llist_for_each_entry_safe(req, tmp, node, io_task_work.node)256		req->io_task_work.func(req, &ts);257	io_submit_flush_completions(ctx);258	mutex_unlock(&ctx->uring_lock);259	percpu_ref_put(&ctx->refs);260}261 262static int io_alloc_hash_table(struct io_hash_table *table, unsigned bits)263{264	unsigned hash_buckets = 1U << bits;265	size_t hash_size = hash_buckets * sizeof(table->hbs[0]);266 267	table->hbs = kmalloc(hash_size, GFP_KERNEL);268	if (!table->hbs)269		return -ENOMEM;270 271	table->hash_bits = bits;272	init_hash_table(table, hash_buckets);273	return 0;274}275 276static HWJS_SUSPENDS __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)277{278	struct io_ring_ctx *ctx;279	int hash_bits;280	bool ret;281 282	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);283	if (!ctx)284		return NULL;285 286	xa_init(&ctx->io_bl_xa);287 288	/*289	 * Use 5 bits less than the max cq entries, that should give us around290	 * 32 entries per hash list if totally full and uniformly spread, but291	 * don't keep too many buckets to not overconsume memory.292	 */293	hash_bits = ilog2(p->cq_entries) - 5;294	hash_bits = clamp(hash_bits, 1, 8);295	if (io_alloc_hash_table(&ctx->cancel_table, hash_bits))296		goto err;297	if (io_alloc_hash_table(&ctx->cancel_table_locked, hash_bits))298		goto err;299	if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,300			    0, GFP_KERNEL))301		goto err;302 303	ctx->flags = p->flags;304	atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT);305	init_waitqueue_head(&ctx->sqo_sq_wait);306	INIT_LIST_HEAD(&ctx->sqd_list);307	INIT_LIST_HEAD(&ctx->cq_overflow_list);308	INIT_LIST_HEAD(&ctx->io_buffers_cache);309	ret = io_alloc_cache_init(&ctx->rsrc_node_cache, IO_NODE_ALLOC_CACHE_MAX,310			    sizeof(struct io_rsrc_node));311	ret |= io_alloc_cache_init(&ctx->apoll_cache, IO_POLL_ALLOC_CACHE_MAX,312			    sizeof(struct async_poll));313	ret |= io_alloc_cache_init(&ctx->netmsg_cache, IO_ALLOC_CACHE_MAX,314			    sizeof(struct io_async_msghdr));315	ret |= io_alloc_cache_init(&ctx->rw_cache, IO_ALLOC_CACHE_MAX,316			    sizeof(struct io_async_rw));317	ret |= io_alloc_cache_init(&ctx->uring_cache, IO_ALLOC_CACHE_MAX,318			    sizeof(struct uring_cache));319	spin_lock_init(&ctx->msg_lock);320	ret |= io_alloc_cache_init(&ctx->msg_cache, IO_ALLOC_CACHE_MAX,321			    sizeof(struct io_kiocb));322	ret |= io_futex_cache_init(ctx);323	if (ret)324		goto free_ref;325	init_completion(&ctx->ref_comp);326	xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);327	mutex_init(&ctx->uring_lock);328	init_waitqueue_head(&ctx->cq_wait);329	init_waitqueue_head(&ctx->poll_wq);330	init_waitqueue_head(&ctx->rsrc_quiesce_wq);331	spin_lock_init(&ctx->completion_lock);332	spin_lock_init(&ctx->timeout_lock);333	INIT_WQ_LIST(&ctx->iopoll_list);334	INIT_LIST_HEAD(&ctx->io_buffers_comp);335	INIT_LIST_HEAD(&ctx->defer_list);336	INIT_LIST_HEAD(&ctx->timeout_list);337	INIT_LIST_HEAD(&ctx->ltimeout_list);338	INIT_LIST_HEAD(&ctx->rsrc_ref_list);339	init_llist_head(&ctx->work_llist);340	INIT_LIST_HEAD(&ctx->tctx_list);341	ctx->submit_state.free_list.next = NULL;342	INIT_HLIST_HEAD(&ctx->waitid_list);343#ifdef CONFIG_FUTEX344	INIT_HLIST_HEAD(&ctx->futex_list);345#endif346	INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);347	INIT_WQ_LIST(&ctx->submit_state.compl_reqs);348	INIT_HLIST_HEAD(&ctx->cancelable_uring_cmd);349	io_napi_init(ctx);350 351	return ctx;352 353free_ref:354	percpu_ref_exit(&ctx->refs);355err:356	io_alloc_cache_free(&ctx->rsrc_node_cache, kfree);357	io_alloc_cache_free(&ctx->apoll_cache, kfree);358	io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free);359	io_alloc_cache_free(&ctx->rw_cache, io_rw_cache_free);360	io_alloc_cache_free(&ctx->uring_cache, kfree);361	io_alloc_cache_free(&ctx->msg_cache, io_msg_cache_free);362	io_futex_cache_free(ctx);363	kfree(ctx->cancel_table.hbs);364	kfree(ctx->cancel_table_locked.hbs);365	xa_destroy(&ctx->io_bl_xa);366	kfree(ctx);367	return NULL;368}369 370static void io_account_cq_overflow(struct io_ring_ctx *ctx)371{372	struct io_rings *r = ctx->rings;373 374	WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1);375	ctx->cq_extra--;376}377 378static bool req_need_defer(struct io_kiocb *req, u32 seq)379{380	if (unlikely(req->flags & REQ_F_IO_DRAIN)) {381		struct io_ring_ctx *ctx = req->ctx;382 383		return seq + READ_ONCE(ctx->cq_extra) != ctx->cached_cq_tail;384	}385 386	return false;387}388 389static HWJS_SUSPENDS void io_clean_op(struct io_kiocb *req)390{391	if (req->flags & REQ_F_BUFFER_SELECTED) {392		spin_lock(&req->ctx->completion_lock);393		io_kbuf_drop(req);394		spin_unlock(&req->ctx->completion_lock);395	}396 397	if (req->flags & REQ_F_NEED_CLEANUP) {398		const struct io_cold_def *def = &io_cold_defs[req->opcode];399 400		if (def->cleanup)401			def->cleanup(req);402	}403	if ((req->flags & REQ_F_POLLED) && req->apoll) {404		kfree(req->apoll->double_poll);405		kfree(req->apoll);406		req->apoll = NULL;407	}408	if (req->flags & REQ_F_INFLIGHT) {409		struct io_uring_task *tctx = req->task->io_uring;410 411		atomic_dec(&tctx->inflight_tracked);412	}413	if (req->flags & REQ_F_CREDS)414		put_cred(req->creds);415	if (req->flags & REQ_F_ASYNC_DATA) {416		kfree(req->async_data);417		req->async_data = NULL;418	}419	req->flags &= ~IO_REQ_CLEAN_FLAGS;420}421 422static inline void io_req_track_inflight(struct io_kiocb *req)423{424	if (!(req->flags & REQ_F_INFLIGHT)) {425		req->flags |= REQ_F_INFLIGHT;426		atomic_inc(&req->task->io_uring->inflight_tracked);427	}428}429 430static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)431{432	if (WARN_ON_ONCE(!req->link))433		return NULL;434 435	req->flags &= ~REQ_F_ARM_LTIMEOUT;436	req->flags |= REQ_F_LINK_TIMEOUT;437 438	/* linked timeouts should have two refs once prep'ed */439	io_req_set_refcount(req);440	__io_req_set_refcount(req->link, 2);441	return req->link;442}443 444static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)445{446	if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT)))447		return NULL;448	return __io_prep_linked_timeout(req);449}450 451static noinline void __io_arm_ltimeout(struct io_kiocb *req)452{453	io_queue_linked_timeout(__io_prep_linked_timeout(req));454}455 456static inline void io_arm_ltimeout(struct io_kiocb *req)457{458	if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT))459		__io_arm_ltimeout(req);460}461 462static void io_prep_async_work(struct io_kiocb *req)463{464	const struct io_issue_def *def = &io_issue_defs[req->opcode];465	struct io_ring_ctx *ctx = req->ctx;466 467	if (!(req->flags & REQ_F_CREDS)) {468		req->flags |= REQ_F_CREDS;469		req->creds = get_current_cred();470	}471 472	req->work.list.next = NULL;473	atomic_set(&req->work.flags, 0);474	if (req->flags & REQ_F_FORCE_ASYNC)475		atomic_or(IO_WQ_WORK_CONCURRENT, &req->work.flags);476 477	if (req->file && !(req->flags & REQ_F_FIXED_FILE))478		req->flags |= io_file_get_flags(req->file);479 480	if (req->file && (req->flags & REQ_F_ISREG)) {481		bool should_hash = def->hash_reg_file;482 483		/* don't serialize this request if the fs doesn't need it */484		if (should_hash && (req->file->f_flags & O_DIRECT) &&485		    (req->file->f_op->fop_flags & FOP_DIO_PARALLEL_WRITE))486			should_hash = false;487		if (should_hash || (ctx->flags & IORING_SETUP_IOPOLL))488			io_wq_hash_work(&req->work, file_inode(req->file));489	} else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) {490		if (def->unbound_nonreg_file)491			atomic_or(IO_WQ_WORK_UNBOUND, &req->work.flags);492	}493}494 495static void io_prep_async_link(struct io_kiocb *req)496{497	struct io_kiocb *cur;498 499	if (req->flags & REQ_F_LINK_TIMEOUT) {500		struct io_ring_ctx *ctx = req->ctx;501 502		spin_lock_irq(&ctx->timeout_lock);503		io_for_each_link(cur, req)504			io_prep_async_work(cur);505		spin_unlock_irq(&ctx->timeout_lock);506	} else {507		io_for_each_link(cur, req)508			io_prep_async_work(cur);509	}510}511 512static HWJS_SUSPENDS void io_queue_iowq(struct io_kiocb *req)513{514	struct io_kiocb *link = io_prep_linked_timeout(req);515	struct io_uring_task *tctx = req->task->io_uring;516 517	BUG_ON(!tctx);518	BUG_ON(!tctx->io_wq);519 520	/* init ->work of the whole link before punting */521	io_prep_async_link(req);522 523	/*524	 * Not expected to happen, but if we do have a bug where this _can_525	 * happen, catch it here and ensure the request is marked as526	 * canceled. That will make io-wq go through the usual work cancel527	 * procedure rather than attempt to run this request (or create a new528	 * worker for it).529	 */530	if (WARN_ON_ONCE(!same_thread_group(req->task, current)))531		atomic_or(IO_WQ_WORK_CANCEL, &req->work.flags);532 533	trace_io_uring_queue_async_work(req, io_wq_is_hashed(&req->work));534	io_wq_enqueue(tctx->io_wq, &req->work);535	if (link)536		io_queue_linked_timeout(link);537}538 539static HWJS_SUSPENDS void io_req_queue_iowq_tw(struct io_kiocb *req, struct io_tw_state *ts)540{541	io_queue_iowq(req);542}543 544void io_req_queue_iowq(struct io_kiocb *req)545{546	req->io_task_work.func = io_req_queue_iowq_tw;547	io_req_task_work_add(req);548}549 550static HWJS_SUSPENDS __cold void io_queue_deferred(struct io_ring_ctx *ctx)551{552	while (!list_empty(&ctx->defer_list)) {553		struct io_defer_entry *de = list_first_entry(&ctx->defer_list,554						struct io_defer_entry, list);555 556		if (req_need_defer(de->req, de->seq))557			break;558		list_del_init(&de->list);559		io_req_task_queue(de->req);560		kfree(de);561	}562}563 564void __io_commit_cqring_flush(struct io_ring_ctx *ctx)565{566	if (ctx->poll_activated)567		io_poll_wq_wake(ctx);568	if (ctx->off_timeout_used)569		io_flush_timeouts(ctx);570	if (ctx->drain_active) {571		spin_lock(&ctx->completion_lock);572		io_queue_deferred(ctx);573		spin_unlock(&ctx->completion_lock);574	}575	if (ctx->has_evfd)576		io_eventfd_flush_signal(ctx);577}578 579static inline void __io_cq_lock(struct io_ring_ctx *ctx)580{581	if (!ctx->lockless_cq)582		spin_lock(&ctx->completion_lock);583}584 585static inline void io_cq_lock(struct io_ring_ctx *ctx)586	__acquires(ctx->completion_lock)587{588	spin_lock(&ctx->completion_lock);589}590 591static HWJS_SUSPENDS inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)592{593	io_commit_cqring(ctx);594	if (!ctx->task_complete) {595		if (!ctx->lockless_cq)596			spin_unlock(&ctx->completion_lock);597		/* IOPOLL rings only need to wake up if it's also SQPOLL */598		if (!ctx->syscall_iopoll)599			io_cqring_wake(ctx);600	}601	io_commit_cqring_flush(ctx);602}603 604static HWJS_SUSPENDS void io_cq_unlock_post(struct io_ring_ctx *ctx)605	__releases(ctx->completion_lock)606{607	io_commit_cqring(ctx);608	spin_unlock(&ctx->completion_lock);609	io_cqring_wake(ctx);610	io_commit_cqring_flush(ctx);611}612 613static HWJS_SUSPENDS void __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool dying)614{615	size_t cqe_size = sizeof(struct io_uring_cqe);616 617	lockdep_assert_held(&ctx->uring_lock);618 619	/* don't abort if we're dying, entries must get freed */620	if (!dying && __io_cqring_events(ctx) == ctx->cq_entries)621		return;622 623	if (ctx->flags & IORING_SETUP_CQE32)624		cqe_size <<= 1;625 626	io_cq_lock(ctx);627	while (!list_empty(&ctx->cq_overflow_list)) {628		struct io_uring_cqe *cqe;629		struct io_overflow_cqe *ocqe;630 631		ocqe = list_first_entry(&ctx->cq_overflow_list,632					struct io_overflow_cqe, list);633 634		if (!dying) {635			if (!io_get_cqe_overflow(ctx, &cqe, true))636				break;637			memcpy(cqe, &ocqe->cqe, cqe_size);638		}639		list_del(&ocqe->list);640		kfree(ocqe);641 642		/*643		 * For silly syzbot cases that deliberately overflow by huge644		 * amounts, check if we need to resched and drop and645		 * reacquire the locks if so. Nothing real would ever hit this.646		 * Ideally we'd have a non-posting unlock for this, but hard647		 * to care for a non-real case.648		 */649		if (need_resched()) {650			io_cq_unlock_post(ctx);651			mutex_unlock(&ctx->uring_lock);652			cond_resched();653			mutex_lock(&ctx->uring_lock);654			io_cq_lock(ctx);655		}656	}657 658	if (list_empty(&ctx->cq_overflow_list)) {659		clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);660		atomic_andnot(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);661	}662	io_cq_unlock_post(ctx);663}664 665static HWJS_SUSPENDS void io_cqring_overflow_kill(struct io_ring_ctx *ctx)666{667	if (ctx->rings)668		__io_cqring_overflow_flush(ctx, true);669}670 671static HWJS_SUSPENDS void io_cqring_do_overflow_flush(struct io_ring_ctx *ctx)672{673	mutex_lock(&ctx->uring_lock);674	__io_cqring_overflow_flush(ctx, false);675	mutex_unlock(&ctx->uring_lock);676}677 678/* can be called by any task */679static HWJS_SUSPENDS void io_put_task_remote(struct task_struct *task)680{681	struct io_uring_task *tctx = task->io_uring;682 683	percpu_counter_sub(&tctx->inflight, 1);684	if (unlikely(atomic_read(&tctx->in_cancel)))685		wake_up(&tctx->wait);686	put_task_struct(task);687}688 689/* used by a task to put its own references */690static void io_put_task_local(struct task_struct *task)691{692	task->io_uring->cached_refs++;693}694 695/* must to be called somewhat shortly after putting a request */696static HWJS_SUSPENDS inline void io_put_task(struct task_struct *task)697{698	if (likely(task == current))699		io_put_task_local(task);700	else701		io_put_task_remote(task);702}703 704void io_task_refs_refill(struct io_uring_task *tctx)705{706	unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR;707 708	percpu_counter_add(&tctx->inflight, refill);709	refcount_add(refill, &current->usage);710	tctx->cached_refs += refill;711}712 713static HWJS_SUSPENDS __cold void io_uring_drop_tctx_refs(struct task_struct *task)714{715	struct io_uring_task *tctx = task->io_uring;716	unsigned int refs = tctx->cached_refs;717 718	if (refs) {719		tctx->cached_refs = 0;720		percpu_counter_sub(&tctx->inflight, refs);721		put_task_struct_many(task, refs);722	}723}724 725static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,726				     s32 res, u32 cflags, u64 extra1, u64 extra2)727{728	struct io_overflow_cqe *ocqe;729	size_t ocq_size = sizeof(struct io_overflow_cqe);730	bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32);731 732	lockdep_assert_held(&ctx->completion_lock);733 734	if (is_cqe32)735		ocq_size += sizeof(struct io_uring_cqe);736 737	ocqe = kmalloc(ocq_size, GFP_ATOMIC | __GFP_ACCOUNT);738	trace_io_uring_cqe_overflow(ctx, user_data, res, cflags, ocqe);739	if (!ocqe) {740		/*741		 * If we're in ring overflow flush mode, or in task cancel mode,742		 * or cannot allocate an overflow entry, then we need to drop it743		 * on the floor.744		 */745		io_account_cq_overflow(ctx);746		set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq);747		return false;748	}749	if (list_empty(&ctx->cq_overflow_list)) {750		set_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);751		atomic_or(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);752 753	}754	ocqe->cqe.user_data = user_data;755	ocqe->cqe.res = res;756	ocqe->cqe.flags = cflags;757	if (is_cqe32) {758		ocqe->cqe.big_cqe[0] = extra1;759		ocqe->cqe.big_cqe[1] = extra2;760	}761	list_add_tail(&ocqe->list, &ctx->cq_overflow_list);762	return true;763}764 765static void io_req_cqe_overflow(struct io_kiocb *req)766{767	io_cqring_event_overflow(req->ctx, req->cqe.user_data,768				req->cqe.res, req->cqe.flags,769				req->big_cqe.extra1, req->big_cqe.extra2);770	memset(&req->big_cqe, 0, sizeof(req->big_cqe));771}772 773/*774 * writes to the cq entry need to come after reading head; the775 * control dependency is enough as we're using WRITE_ONCE to776 * fill the cq entry777 */778bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow)779{780	struct io_rings *rings = ctx->rings;781	unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);782	unsigned int free, queued, len;783 784	/*785	 * Posting into the CQ when there are pending overflowed CQEs may break786	 * ordering guarantees, which will affect links, F_MORE users and more.787	 * Force overflow the completion.788	 */789	if (!overflow && (ctx->check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)))790		return false;791 792	/* userspace may cheat modifying the tail, be safe and do min */793	queued = min(__io_cqring_events(ctx), ctx->cq_entries);794	free = ctx->cq_entries - queued;795	/* we need a contiguous range, limit based on the current array offset */796	len = min(free, ctx->cq_entries - off);797	if (!len)798		return false;799 800	if (ctx->flags & IORING_SETUP_CQE32) {801		off <<= 1;802		len <<= 1;803	}804 805	ctx->cqe_cached = &rings->cqes[off];806	ctx->cqe_sentinel = ctx->cqe_cached + len;807	return true;808}809 810static bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res,811			      u32 cflags)812{813	struct io_uring_cqe *cqe;814 815	ctx->cq_extra++;816 817	/*818	 * If we can't get a cq entry, userspace overflowed the819	 * submission (by quite a lot). Increment the overflow count in820	 * the ring.821	 */822	if (likely(io_get_cqe(ctx, &cqe))) {823		trace_io_uring_complete(ctx, NULL, user_data, res, cflags, 0, 0);824 825		WRITE_ONCE(cqe->user_data, user_data);826		WRITE_ONCE(cqe->res, res);827		WRITE_ONCE(cqe->flags, cflags);828 829		if (ctx->flags & IORING_SETUP_CQE32) {830			WRITE_ONCE(cqe->big_cqe[0], 0);831			WRITE_ONCE(cqe->big_cqe[1], 0);832		}833		return true;834	}835	return false;836}837 838static bool __io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res,839			      u32 cflags)840{841	bool filled;842 843	filled = io_fill_cqe_aux(ctx, user_data, res, cflags);844	if (!filled)845		filled = io_cqring_event_overflow(ctx, user_data, res, cflags, 0, 0);846 847	return filled;848}849 850bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags)851{852	bool filled;853 854	io_cq_lock(ctx);855	filled = __io_post_aux_cqe(ctx, user_data, res, cflags);856	io_cq_unlock_post(ctx);857	return filled;858}859 860/*861 * Must be called from inline task_work so we now a flush will happen later,862 * and obviously with ctx->uring_lock held (tw always has that).863 */864void io_add_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags)865{866	if (!io_fill_cqe_aux(ctx, user_data, res, cflags)) {867		spin_lock(&ctx->completion_lock);868		io_cqring_event_overflow(ctx, user_data, res, cflags, 0, 0);869		spin_unlock(&ctx->completion_lock);870	}871	ctx->submit_state.cq_flush = true;872}873 874/*875 * A helper for multishot requests posting additional CQEs.876 * Should only be used from a task_work including IO_URING_F_MULTISHOT.877 */878bool io_req_post_cqe(struct io_kiocb *req, s32 res, u32 cflags)879{880	struct io_ring_ctx *ctx = req->ctx;881	bool posted;882 883	lockdep_assert(!io_wq_current_is_worker());884	lockdep_assert_held(&ctx->uring_lock);885 886	__io_cq_lock(ctx);887	posted = io_fill_cqe_aux(ctx, req->cqe.user_data, res, cflags);888	ctx->submit_state.cq_flush = true;889	__io_cq_unlock_post(ctx);890	return posted;891}892 893static HWJS_SUSPENDS void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags)894{895	struct io_ring_ctx *ctx = req->ctx;896 897	/*898	 * All execution paths but io-wq use the deferred completions by899	 * passing IO_URING_F_COMPLETE_DEFER and thus should not end up here.900	 */901	if (WARN_ON_ONCE(!(issue_flags & IO_URING_F_IOWQ)))902		return;903 904	/*905	 * Handle special CQ sync cases via task_work. DEFER_TASKRUN requires906	 * the submitter task context, IOPOLL protects with uring_lock.907	 */908	if (ctx->task_complete || (ctx->flags & IORING_SETUP_IOPOLL)) {909		req->io_task_work.func = io_req_task_complete;910		io_req_task_work_add(req);911		return;912	}913 914	io_cq_lock(ctx);915	if (!(req->flags & REQ_F_CQE_SKIP)) {916		if (!io_fill_cqe_req(ctx, req))917			io_req_cqe_overflow(req);918	}919	io_cq_unlock_post(ctx);920 921	/*922	 * We don't free the request here because we know it's called from923	 * io-wq only, which holds a reference, so it cannot be the last put.924	 */925	req_ref_put(req);926}927 928void io_req_defer_failed(struct io_kiocb *req, s32 res)929	__must_hold(&ctx->uring_lock)930{931	const struct io_cold_def *def = &io_cold_defs[req->opcode];932 933	lockdep_assert_held(&req->ctx->uring_lock);934 935	req_set_fail(req);936	io_req_set_res(req, res, io_put_kbuf(req, res, IO_URING_F_UNLOCKED));937	if (def->fail)938		def->fail(req);939	io_req_complete_defer(req);940}941 942/*943 * Don't initialise the fields below on every allocation, but do that in944 * advance and keep them valid across allocations.945 */946static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)947{948	req->ctx = ctx;949	req->link = NULL;950	req->async_data = NULL;951	/* not necessary, but safer to zero */952	memset(&req->cqe, 0, sizeof(req->cqe));953	memset(&req->big_cqe, 0, sizeof(req->big_cqe));954}955 956/*957 * A request might get retired back into the request caches even before opcode958 * handlers and io_issue_sqe() are done with it, e.g. inline completion path.959 * Because of that, io_alloc_req() should be called only under ->uring_lock960 * and with extra caution to not get a request that is still worked on.961 */962__cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx)963	__must_hold(&ctx->uring_lock)964{965	gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;966	void *reqs[IO_REQ_ALLOC_BATCH];967	int ret;968 969	ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs);970 971	/*972	 * Bulk alloc is all-or-nothing. If we fail to get a batch,973	 * retry single alloc to be on the safe side.974	 */975	if (unlikely(ret <= 0)) {976		reqs[0] = kmem_cache_alloc(req_cachep, gfp);977		if (!reqs[0])978			return false;979		ret = 1;980	}981 982	percpu_ref_get_many(&ctx->refs, ret);983	while (ret--) {984		struct io_kiocb *req = reqs[ret];985 986		io_preinit_req(req, ctx);987		io_req_add_to_cache(req, ctx);988	}989	return true;990}991 992__cold void io_free_req(struct io_kiocb *req)993{994	/* refs were already put, restore them for io_req_task_complete() */995	req->flags &= ~REQ_F_REFCOUNT;996	/* we only want to free it, don't post CQEs */997	req->flags |= REQ_F_CQE_SKIP;998	req->io_task_work.func = io_req_task_complete;999	io_req_task_work_add(req);1000}1001 1002static void __io_req_find_next_prep(struct io_kiocb *req)1003{1004	struct io_ring_ctx *ctx = req->ctx;1005 1006	spin_lock(&ctx->completion_lock);1007	io_disarm_next(req);1008	spin_unlock(&ctx->completion_lock);1009}1010 1011static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)1012{1013	struct io_kiocb *nxt;1014 1015	/*1016	 * If LINK is set, we have dependent requests in this chain. If we1017	 * didn't fail this request, queue the first one up, moving any other1018	 * dependencies to the next request. In case of failure, fail the rest1019	 * of the chain.1020	 */1021	if (unlikely(req->flags & IO_DISARM_MASK))1022		__io_req_find_next_prep(req);1023	nxt = req->link;1024	req->link = NULL;1025	return nxt;1026}1027 1028static HWJS_SUSPENDS void ctx_flush_and_put(struct io_ring_ctx *ctx, struct io_tw_state *ts)1029{1030	if (!ctx)1031		return;1032	if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)1033		atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);1034 1035	io_submit_flush_completions(ctx);1036	mutex_unlock(&ctx->uring_lock);1037	percpu_ref_put(&ctx->refs);1038}1039 1040/*1041 * Run queued task_work, returning the number of entries processed in *count.1042 * If more entries than max_entries are available, stop processing once this1043 * is reached and return the rest of the list.1044 */1045struct llist_node *io_handle_tw_list(struct llist_node *node,1046				     unsigned int *count,1047				     unsigned int max_entries)1048{1049	struct io_ring_ctx *ctx = NULL;1050	struct io_tw_state ts = { };1051 1052	do {1053		struct llist_node *next = node->next;1054		struct io_kiocb *req = container_of(node, struct io_kiocb,1055						    io_task_work.node);1056 1057		if (req->ctx != ctx) {1058			ctx_flush_and_put(ctx, &ts);1059			ctx = req->ctx;1060			mutex_lock(&ctx->uring_lock);1061			percpu_ref_get(&ctx->refs);1062		}1063		INDIRECT_CALL_2(req->io_task_work.func,1064				io_poll_task_func, io_req_rw_complete,1065				req, &ts);1066		node = next;1067		(*count)++;1068		if (unlikely(need_resched())) {1069			ctx_flush_and_put(ctx, &ts);1070			ctx = NULL;1071			cond_resched();1072		}1073	} while (node && *count < max_entries);1074 1075	ctx_flush_and_put(ctx, &ts);1076	return node;1077}1078 1079/**1080 * io_llist_xchg - swap all entries in a lock-less list1081 * @head:	the head of lock-less list to delete all entries1082 * @new:	new entry as the head of the list1083 *1084 * If list is empty, return NULL, otherwise, return the pointer to the first entry.1085 * The order of entries returned is from the newest to the oldest added one.1086 */1087static inline struct llist_node *io_llist_xchg(struct llist_head *head,1088					       struct llist_node *new)1089{1090	return xchg(&head->first, new);1091}1092 1093static HWJS_SUSPENDS __cold void io_fallback_tw(struct io_uring_task *tctx, bool sync)1094{1095	struct llist_node *node = llist_del_all(&tctx->task_list);1096	struct io_ring_ctx *last_ctx = NULL;1097	struct io_kiocb *req;1098 1099	while (node) {1100		req = container_of(node, struct io_kiocb, io_task_work.node);1101		node = node->next;1102		if (sync && last_ctx != req->ctx) {1103			if (last_ctx) {1104				flush_delayed_work(&last_ctx->fallback_work);1105				percpu_ref_put(&last_ctx->refs);1106			}1107			last_ctx = req->ctx;1108			percpu_ref_get(&last_ctx->refs);1109		}1110		if (llist_add(&req->io_task_work.node,1111			      &req->ctx->fallback_llist))1112			schedule_delayed_work(&req->ctx->fallback_work, 1);1113	}1114 1115	if (last_ctx) {1116		flush_delayed_work(&last_ctx->fallback_work);1117		percpu_ref_put(&last_ctx->refs);1118	}1119}1120 1121struct llist_node *tctx_task_work_run(struct io_uring_task *tctx,1122				      unsigned int max_entries,1123				      unsigned int *count)1124{1125	struct llist_node *node;1126 1127	if (unlikely(current->flags & PF_EXITING)) {1128		io_fallback_tw(tctx, true);1129		return NULL;1130	}1131 1132	node = llist_del_all(&tctx->task_list);1133	if (node) {1134		node = llist_reverse_order(node);1135		node = io_handle_tw_list(node, count, max_entries);1136	}1137 1138	/* relaxed read is enough as only the task itself sets ->in_cancel */1139	if (unlikely(atomic_read(&tctx->in_cancel)))1140		io_uring_drop_tctx_refs(current);1141 1142	trace_io_uring_task_work_run(tctx, *count);1143	return node;1144}1145 1146void tctx_task_work(struct callback_head *cb)1147{1148	struct io_uring_task *tctx;1149	struct llist_node *ret;1150	unsigned int count = 0;1151 1152	tctx = container_of(cb, struct io_uring_task, task_work);1153	ret = tctx_task_work_run(tctx, UINT_MAX, &count);1154	/* can't happen */1155	WARN_ON_ONCE(ret);1156}1157 1158static HWJS_SUSPENDS inline void io_req_local_work_add(struct io_kiocb *req,1159					 struct io_ring_ctx *ctx,1160					 unsigned flags)1161{1162	unsigned nr_wait, nr_tw, nr_tw_prev;1163	struct llist_node *head;1164 1165	/* See comment above IO_CQ_WAKE_INIT */1166	BUILD_BUG_ON(IO_CQ_WAKE_FORCE <= IORING_MAX_CQ_ENTRIES);1167 1168	/*1169	 * We don't know how many reuqests is there in the link and whether1170	 * they can even be queued lazily, fall back to non-lazy.1171	 */1172	if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK))1173		flags &= ~IOU_F_TWQ_LAZY_WAKE;1174 1175	guard(rcu)();1176 1177	head = READ_ONCE(ctx->work_llist.first);1178	do {1179		nr_tw_prev = 0;1180		if (head) {1181			struct io_kiocb *first_req = container_of(head,1182							struct io_kiocb,1183							io_task_work.node);1184			/*1185			 * Might be executed at any moment, rely on1186			 * SLAB_TYPESAFE_BY_RCU to keep it alive.1187			 */1188			nr_tw_prev = READ_ONCE(first_req->nr_tw);1189		}1190 1191		/*1192		 * Theoretically, it can overflow, but that's fine as one of1193		 * previous adds should've tried to wake the task.1194		 */1195		nr_tw = nr_tw_prev + 1;1196		if (!(flags & IOU_F_TWQ_LAZY_WAKE))1197			nr_tw = IO_CQ_WAKE_FORCE;1198 1199		req->nr_tw = nr_tw;1200		req->io_task_work.node.next = head;1201	} while (!try_cmpxchg(&ctx->work_llist.first, &head,1202			      &req->io_task_work.node));1203 1204	/*1205	 * cmpxchg implies a full barrier, which pairs with the barrier1206	 * in set_current_state() on the io_cqring_wait() side. It's used1207	 * to ensure that either we see updated ->cq_wait_nr, or waiters1208	 * going to sleep will observe the work added to the list, which1209	 * is similar to the wait/wawke task state sync.1210	 */1211 1212	if (!head) {1213		if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)1214			atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);1215		if (ctx->has_evfd)1216			io_eventfd_signal(ctx);1217	}1218 1219	nr_wait = atomic_read(&ctx->cq_wait_nr);1220	/* not enough or no one is waiting */1221	if (nr_tw < nr_wait)1222		return;1223	/* the previous add has already woken it up */1224	if (nr_tw_prev >= nr_wait)1225		return;1226	wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE);1227}1228 1229static HWJS_SUSPENDS void io_req_normal_work_add(struct io_kiocb *req)1230{1231	struct io_uring_task *tctx = req->task->io_uring;1232	struct io_ring_ctx *ctx = req->ctx;1233 1234	/* task_work already pending, we're done */1235	if (!llist_add(&req->io_task_work.node, &tctx->task_list))1236		return;1237 1238	if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)1239		atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);1240 1241	/* SQPOLL doesn't need the task_work added, it'll run it itself */1242	if (ctx->flags & IORING_SETUP_SQPOLL) {1243		struct io_sq_data *sqd = ctx->sq_data;1244 1245		if (sqd->thread)1246			__set_notify_signal(sqd->thread);1247		return;1248	}1249 1250	if (likely(!task_work_add(req->task, &tctx->task_work, ctx->notify_method)))1251		return;1252 1253	io_fallback_tw(tctx, false);1254}1255 1256void __io_req_task_work_add(struct io_kiocb *req, unsigned flags)1257{1258	if (req->ctx->flags & IORING_SETUP_DEFER_TASKRUN)1259		io_req_local_work_add(req, req->ctx, flags);1260	else1261		io_req_normal_work_add(req);1262}1263 1264void io_req_task_work_add_remote(struct io_kiocb *req, struct io_ring_ctx *ctx,1265				 unsigned flags)1266{1267	if (WARN_ON_ONCE(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)))1268		return;1269	io_req_local_work_add(req, ctx, flags);1270}1271 1272static HWJS_SUSPENDS void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)1273{1274	struct llist_node *node;1275 1276	node = llist_del_all(&ctx->work_llist);1277	while (node) {1278		struct io_kiocb *req = container_of(node, struct io_kiocb,1279						    io_task_work.node);1280 1281		node = node->next;1282		io_req_normal_work_add(req);1283	}1284}1285 1286static bool io_run_local_work_continue(struct io_ring_ctx *ctx, int events,1287				       int min_events)1288{1289	if (llist_empty(&ctx->work_llist))1290		return false;1291	if (events < min_events)1292		return true;1293	if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)1294		atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);1295	return false;1296}1297 1298static HWJS_SUSPENDS int __io_run_local_work(struct io_ring_ctx *ctx, struct io_tw_state *ts,1299			       int min_events)1300{1301	struct llist_node *node;1302	unsigned int loops = 0;1303	int ret = 0;1304 1305	if (WARN_ON_ONCE(ctx->submitter_task != current))1306		return -EEXIST;1307	if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)1308		atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);1309again:1310	/*1311	 * llists are in reverse order, flip it back the right way before1312	 * running the pending items.1313	 */1314	node = llist_reverse_order(io_llist_xchg(&ctx->work_llist, NULL));1315	while (node) {1316		struct llist_node *next = node->next;1317		struct io_kiocb *req = container_of(node, struct io_kiocb,1318						    io_task_work.node);1319		INDIRECT_CALL_2(req->io_task_work.func,1320				io_poll_task_func, io_req_rw_complete,1321				req, ts);1322		ret++;1323		node = next;1324	}1325	loops++;1326 1327	if (io_run_local_work_continue(ctx, ret, min_events))1328		goto again;1329	io_submit_flush_completions(ctx);1330	if (io_run_local_work_continue(ctx, ret, min_events))1331		goto again;1332 1333	trace_io_uring_local_work_run(ctx, ret, loops);1334	return ret;1335}1336 1337static HWJS_SUSPENDS inline int io_run_local_work_locked(struct io_ring_ctx *ctx,1338					   int min_events)1339{1340	struct io_tw_state ts = {};1341 1342	if (llist_empty(&ctx->work_llist))1343		return 0;1344	return __io_run_local_work(ctx, &ts, min_events);1345}1346 1347static HWJS_SUSPENDS int io_run_local_work(struct io_ring_ctx *ctx, int min_events)1348{1349	struct io_tw_state ts = {};1350	int ret;1351 1352	mutex_lock(&ctx->uring_lock);1353	ret = __io_run_local_work(ctx, &ts, min_events);1354	mutex_unlock(&ctx->uring_lock);1355	return ret;1356}1357 1358static HWJS_SUSPENDS void io_req_task_cancel(struct io_kiocb *req, struct io_tw_state *ts)1359{1360	io_tw_lock(req->ctx, ts);1361	io_req_defer_failed(req, req->cqe.res);1362}1363 1364void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts)1365{1366	io_tw_lock(req->ctx, ts);1367	/* req->task == current here, checking PF_EXITING is safe */1368	if (unlikely(req->task->flags & PF_EXITING))1369		io_req_defer_failed(req, -EFAULT);1370	else if (req->flags & REQ_F_FORCE_ASYNC)1371		io_queue_iowq(req);1372	else1373		io_queue_sqe(req);1374}1375 1376void io_req_task_queue_fail(struct io_kiocb *req, int ret)1377{1378	io_req_set_res(req, ret, 0);1379	req->io_task_work.func = io_req_task_cancel;1380	io_req_task_work_add(req);1381}1382 1383void io_req_task_queue(struct io_kiocb *req)1384{1385	req->io_task_work.func = io_req_task_submit;1386	io_req_task_work_add(req);1387}1388 1389void io_queue_next(struct io_kiocb *req)1390{1391	struct io_kiocb *nxt = io_req_find_next(req);1392 1393	if (nxt)1394		io_req_task_queue(nxt);1395}1396 1397static HWJS_SUSPENDS void io_free_batch_list(struct io_ring_ctx *ctx,1398			       struct io_wq_work_node *node)1399	__must_hold(&ctx->uring_lock)1400{1401	do {1402		struct io_kiocb *req = container_of(node, struct io_kiocb,1403						    comp_list);1404 1405		if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) {1406			if (req->flags & REQ_F_REFCOUNT) {1407				node = req->comp_list.next;1408				if (!req_ref_put_and_test(req))1409					continue;1410			}1411			if ((req->flags & REQ_F_POLLED) && req->apoll) {1412				struct async_poll *apoll = req->apoll;1413 1414				if (apoll->double_poll)1415					kfree(apoll->double_poll);1416				if (!io_alloc_cache_put(&ctx->apoll_cache, apoll))1417					kfree(apoll);1418				req->flags &= ~REQ_F_POLLED;1419			}1420			if (req->flags & IO_REQ_LINK_FLAGS)1421				io_queue_next(req);1422			if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))1423				io_clean_op(req);1424		}1425		io_put_file(req);1426		io_put_rsrc_node(ctx, req->rsrc_node);1427		io_put_task(req->task);1428 1429		node = req->comp_list.next;1430		io_req_add_to_cache(req, ctx);1431	} while (node);1432}1433 1434void __io_submit_flush_completions(struct io_ring_ctx *ctx)1435	__must_hold(&ctx->uring_lock)1436{1437	struct io_submit_state *state = &ctx->submit_state;1438	struct io_wq_work_node *node;1439 1440	__io_cq_lock(ctx);1441	__wq_list_for_each(node, &state->compl_reqs) {1442		struct io_kiocb *req = container_of(node, struct io_kiocb,1443					    comp_list);1444 1445		if (!(req->flags & REQ_F_CQE_SKIP) &&1446		    unlikely(!io_fill_cqe_req(ctx, req))) {1447			if (ctx->lockless_cq) {1448				spin_lock(&ctx->completion_lock);1449				io_req_cqe_overflow(req);1450				spin_unlock(&ctx->completion_lock);1451			} else {1452				io_req_cqe_overflow(req);1453			}1454		}1455	}1456	__io_cq_unlock_post(ctx);1457 1458	if (!wq_list_empty(&state->compl_reqs)) {1459		io_free_batch_list(ctx, state->compl_reqs.first);1460		INIT_WQ_LIST(&state->compl_reqs);1461	}1462	ctx->submit_state.cq_flush = false;1463}1464 1465static unsigned io_cqring_events(struct io_ring_ctx *ctx)1466{1467	/* See comment at the top of this file */1468	smp_rmb();1469	return __io_cqring_events(ctx);1470}1471 1472/*1473 * We can't just wait for polled events to come to us, we have to actively1474 * find and complete them.1475 */1476static HWJS_SUSPENDS __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)1477{1478	if (!(ctx->flags & IORING_SETUP_IOPOLL))1479		return;1480 1481	mutex_lock(&ctx->uring_lock);1482	while (!wq_list_empty(&ctx->iopoll_list)) {1483		/* let it sleep and repeat later if can't complete a request */1484		if (io_do_iopoll(ctx, true) == 0)1485			break;1486		/*1487		 * Ensure we allow local-to-the-cpu processing to take place,1488		 * in this case we need to ensure that we reap all events.1489		 * Also let task_work, etc. to progress by releasing the mutex1490		 */1491		if (need_resched()) {1492			mutex_unlock(&ctx->uring_lock);1493			cond_resched();1494			mutex_lock(&ctx->uring_lock);1495		}1496	}1497	mutex_unlock(&ctx->uring_lock);1498}1499 1500static HWJS_SUSPENDS int io_iopoll_check(struct io_ring_ctx *ctx, long min)1501{1502	unsigned int nr_events = 0;1503	unsigned long check_cq;1504 1505	lockdep_assert_held(&ctx->uring_lock);1506 1507	if (!io_allowed_run_tw(ctx))1508		return -EEXIST;1509 1510	check_cq = READ_ONCE(ctx->check_cq);1511	if (unlikely(check_cq)) {1512		if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))1513			__io_cqring_overflow_flush(ctx, false);1514		/*1515		 * Similarly do not spin if we have not informed the user of any1516		 * dropped CQE.1517		 */1518		if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT))1519			return -EBADR;1520	}1521	/*1522	 * Don't enter poll loop if we already have events pending.1523	 * If we do, we can potentially be spinning for commands that1524	 * already triggered a CQE (eg in error).1525	 */1526	if (io_cqring_events(ctx))1527		return 0;1528 1529	do {1530		int ret = 0;1531 1532		/*1533		 * If a submit got punted to a workqueue, we can have the1534		 * application entering polling for a command before it gets1535		 * issued. That app will hold the uring_lock for the duration1536		 * of the poll right here, so we need to take a breather every1537		 * now and then to ensure that the issue has a chance to add1538		 * the poll to the issued list. Otherwise we can spin here1539		 * forever, while the workqueue is stuck trying to acquire the1540		 * very same mutex.1541		 */1542		if (wq_list_empty(&ctx->iopoll_list) ||1543		    io_task_work_pending(ctx)) {1544			u32 tail = ctx->cached_cq_tail;1545 1546			(void) io_run_local_work_locked(ctx, min);1547 1548			if (task_work_pending(current) ||1549			    wq_list_empty(&ctx->iopoll_list)) {1550				mutex_unlock(&ctx->uring_lock);1551				io_run_task_work();1552				mutex_lock(&ctx->uring_lock);1553			}1554			/* some requests don't go through iopoll_list */1555			if (tail != ctx->cached_cq_tail ||1556			    wq_list_empty(&ctx->iopoll_list))1557				break;1558		}1559		ret = io_do_iopoll(ctx, !min);1560		if (unlikely(ret < 0))1561			return ret;1562 1563		if (task_sigpending(current))1564			return -EINTR;1565		if (need_resched())1566			break;1567 1568		nr_events += ret;1569	} while (nr_events < min);1570 1571	return 0;1572}1573 1574void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts)1575{1576	io_req_complete_defer(req);1577}1578 1579/*1580 * After the iocb has been issued, it's safe to be found on the poll list.1581 * Adding the kiocb to the list AFTER submission ensures that we don't1582 * find it from a io_do_iopoll() thread before the issuer is done1583 * accessing the kiocb cookie.1584 */1585static HWJS_SUSPENDS void io_iopoll_req_issued(struct io_kiocb *req, unsigned int issue_flags)1586{1587	struct io_ring_ctx *ctx = req->ctx;1588	const bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;1589 1590	/* workqueue context doesn't hold uring_lock, grab it now */1591	if (unlikely(needs_lock))1592		mutex_lock(&ctx->uring_lock);1593 1594	/*1595	 * Track whether we have multiple files in our lists. This will impact1596	 * how we do polling eventually, not spinning if we're on potentially1597	 * different devices.1598	 */1599	if (wq_list_empty(&ctx->iopoll_list)) {1600		ctx->poll_multi_queue = false;1601	} else if (!ctx->poll_multi_queue) {1602		struct io_kiocb *list_req;1603 1604		list_req = container_of(ctx->iopoll_list.first, struct io_kiocb,1605					comp_list);1606		if (list_req->file != req->file)1607			ctx->poll_multi_queue = true;1608	}1609 1610	/*1611	 * For fast devices, IO may have already completed. If it has, add1612	 * it to the front so we find it first.1613	 */1614	if (READ_ONCE(req->iopoll_completed))1615		wq_list_add_head(&req->comp_list, &ctx->iopoll_list);1616	else1617		wq_list_add_tail(&req->comp_list, &ctx->iopoll_list);1618 1619	if (unlikely(needs_lock)) {1620		/*1621		 * If IORING_SETUP_SQPOLL is enabled, sqes are either handle1622		 * in sq thread task context or in io worker task context. If1623		 * current task context is sq thread, we don't need to check1624		 * whether should wake up sq thread.1625		 */1626		if ((ctx->flags & IORING_SETUP_SQPOLL) &&1627		    wq_has_sleeper(&ctx->sq_data->wait))1628			wake_up(&ctx->sq_data->wait);1629 1630		mutex_unlock(&ctx->uring_lock);1631	}1632}1633 1634io_req_flags_t io_file_get_flags(struct file *file)1635{1636	io_req_flags_t res = 0;1637 1638	if (S_ISREG(file_inode(file)->i_mode))1639		res |= REQ_F_ISREG;1640	if ((file->f_flags & O_NONBLOCK) || (file->f_mode & FMODE_NOWAIT))1641		res |= REQ_F_SUPPORT_NOWAIT;1642	return res;1643}1644 1645bool io_alloc_async_data(struct io_kiocb *req)1646{1647	const struct io_issue_def *def = &io_issue_defs[req->opcode];1648 1649	WARN_ON_ONCE(!def->async_size);1650	req->async_data = kmalloc(def->async_size, GFP_KERNEL);1651	if (req->async_data) {1652		req->flags |= REQ_F_ASYNC_DATA;1653		return false;1654	}1655	return true;1656}1657 1658static u32 io_get_sequence(struct io_kiocb *req)1659{1660	u32 seq = req->ctx->cached_sq_head;1661	struct io_kiocb *cur;1662 1663	/* need original cached_sq_head, but it was increased for each req */1664	io_for_each_link(cur, req)1665		seq--;1666	return seq;1667}1668 1669static HWJS_SUSPENDS __cold void io_drain_req(struct io_kiocb *req)1670	__must_hold(&ctx->uring_lock)1671{1672	struct io_ring_ctx *ctx = req->ctx;1673	struct io_defer_entry *de;1674	int ret;1675	u32 seq = io_get_sequence(req);1676 1677	/* Still need defer if there is pending req in defer list. */1678	spin_lock(&ctx->completion_lock);1679	if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) {1680		spin_unlock(&ctx->completion_lock);1681queue:1682		ctx->drain_active = false;1683		io_req_task_queue(req);1684		return;1685	}1686	spin_unlock(&ctx->completion_lock);1687 1688	io_prep_async_link(req);1689	de = kmalloc(sizeof(*de), GFP_KERNEL);1690	if (!de) {1691		ret = -ENOMEM;1692		io_req_defer_failed(req, ret);1693		return;1694	}1695 1696	spin_lock(&ctx->completion_lock);1697	if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {1698		spin_unlock(&ctx->completion_lock);1699		kfree(de);1700		goto queue;1701	}1702 1703	trace_io_uring_defer(req);1704	de->req = req;1705	de->seq = seq;1706	list_add_tail(&de->list, &ctx->defer_list);1707	spin_unlock(&ctx->completion_lock);1708}1709 1710static HWJS_SUSPENDS bool io_assign_file(struct io_kiocb *req, const struct io_issue_def *def,1711			   unsigned int issue_flags)1712{1713	if (req->file || !def->needs_file)1714		return true;1715 1716	if (req->flags & REQ_F_FIXED_FILE)1717		req->file = io_file_get_fixed(req, req->cqe.fd, issue_flags);1718	else1719		req->file = io_file_get_normal(req, req->cqe.fd);1720 1721	return !!req->file;1722}1723 1724static HWJS_SUSPENDS int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)1725{1726	const struct io_issue_def *def = &io_issue_defs[req->opcode];1727	const struct cred *creds = NULL;1728	int ret;1729 1730	if (unlikely(!io_assign_file(req, def, issue_flags)))1731		return -EBADF;1732 1733	if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred()))1734		creds = override_creds(req->creds);1735 1736	if (!def->audit_skip)1737		audit_uring_entry(req->opcode);1738 1739	ret = def->issue(req, issue_flags);1740 1741	if (!def->audit_skip)1742		audit_uring_exit(!ret, ret);1743 1744	if (creds)1745		revert_creds(creds);1746 1747	if (ret == IOU_OK) {1748		if (issue_flags & IO_URING_F_COMPLETE_DEFER)1749			io_req_complete_defer(req);1750		else1751			io_req_complete_post(req, issue_flags);1752 1753		return 0;1754	}1755 1756	if (ret == IOU_ISSUE_SKIP_COMPLETE) {1757		ret = 0;1758		io_arm_ltimeout(req);1759 1760		/* If the op doesn't have a file, we're not polling for it */1761		if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue)1762			io_iopoll_req_issued(req, issue_flags);1763	}1764	return ret;1765}1766 1767int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts)1768{1769	io_tw_lock(req->ctx, ts);1770	return io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_MULTISHOT|1771				 IO_URING_F_COMPLETE_DEFER);1772}1773 1774struct io_wq_work *io_wq_free_work(struct io_wq_work *work)1775{1776	struct io_kiocb *req = container_of(work, struct io_kiocb, work);1777	struct io_kiocb *nxt = NULL;1778 1779	if (req_ref_put_and_test(req)) {1780		if (req->flags & IO_REQ_LINK_FLAGS)1781			nxt = io_req_find_next(req);1782		io_free_req(req);1783	}1784	return nxt ? &nxt->work : NULL;1785}1786 1787void io_wq_submit_work(struct io_wq_work *work)1788{1789	struct io_kiocb *req = container_of(work, struct io_kiocb, work);1790	const struct io_issue_def *def = &io_issue_defs[req->opcode];1791	unsigned int issue_flags = IO_URING_F_UNLOCKED | IO_URING_F_IOWQ;1792	bool needs_poll = false;1793	int ret = 0, err = -ECANCELED;1794 1795	/* one will be dropped by ->io_wq_free_work() after returning to io-wq */1796	if (!(req->flags & REQ_F_REFCOUNT))1797		__io_req_set_refcount(req, 2);1798	else1799		req_ref_get(req);1800 1801	io_arm_ltimeout(req);1802 1803	/* either cancelled or io-wq is dying, so don't touch tctx->iowq */1804	if (atomic_read(&work->flags) & IO_WQ_WORK_CANCEL) {1805fail:1806		io_req_task_queue_fail(req, err);1807		return;1808	}1809	if (!io_assign_file(req, def, issue_flags)) {1810		err = -EBADF;1811		atomic_or(IO_WQ_WORK_CANCEL, &work->flags);1812		goto fail;1813	}1814 1815	/*1816	 * If DEFER_TASKRUN is set, it's only allowed to post CQEs from the1817	 * submitter task context. Final request completions are handed to the1818	 * right context, however this is not the case of auxiliary CQEs,1819	 * which is the main mean of operation for multishot requests.1820	 * Don't allow any multishot execution from io-wq. It's more restrictive1821	 * than necessary and also cleaner.1822	 */1823	if (req->flags & REQ_F_APOLL_MULTISHOT) {1824		err = -EBADFD;1825		if (!io_file_can_poll(req))1826			goto fail;1827		if (req->file->f_flags & O_NONBLOCK ||1828		    req->file->f_mode & FMODE_NOWAIT) {1829			err = -ECANCELED;1830			if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)1831				goto fail;1832			return;1833		} else {1834			req->flags &= ~REQ_F_APOLL_MULTISHOT;1835		}1836	}1837 1838	if (req->flags & REQ_F_FORCE_ASYNC) {1839		bool opcode_poll = def->pollin || def->pollout;1840 1841		if (opcode_poll && io_file_can_poll(req)) {1842			needs_poll = true;1843			issue_flags |= IO_URING_F_NONBLOCK;1844		}1845	}1846 1847	do {1848		ret = io_issue_sqe(req, issue_flags);1849		if (ret != -EAGAIN)1850			break;1851 1852		/*1853		 * If REQ_F_NOWAIT is set, then don't wait or retry with1854		 * poll. -EAGAIN is final for that case.1855		 */1856		if (req->flags & REQ_F_NOWAIT)1857			break;1858 1859		/*1860		 * We can get EAGAIN for iopolled IO even though we're1861		 * forcing a sync submission from here, since we can't1862		 * wait for request slots on the block side.1863		 */1864		if (!needs_poll) {1865			if (!(req->ctx->flags & IORING_SETUP_IOPOLL))1866				break;1867			if (io_wq_worker_stopped())1868				break;1869			cond_resched();1870			continue;1871		}1872 1873		if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK)1874			return;1875		/* aborted or ready, in either case retry blocking */1876		needs_poll = false;1877		issue_flags &= ~IO_URING_F_NONBLOCK;1878	} while (1);1879 1880	/* avoid locking problems by failing it from a clean context */1881	if (ret)1882		io_req_task_queue_fail(req, ret);1883}1884 1885inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,1886				      unsigned int issue_flags)1887{1888	struct io_ring_ctx *ctx = req->ctx;1889	struct io_fixed_file *slot;1890	struct file *file = NULL;1891 1892	io_ring_submit_lock(ctx, issue_flags);1893 1894	if (unlikely((unsigned int)fd >= ctx->nr_user_files))1895		goto out;1896	fd = array_index_nospec(fd, ctx->nr_user_files);1897	slot = io_fixed_file_slot(&ctx->file_table, fd);1898	if (!req->rsrc_node)1899		__io_req_set_rsrc_node(req, ctx);1900	req->flags |= io_slot_flags(slot);1901	file = io_slot_file(slot);1902out:1903	io_ring_submit_unlock(ctx, issue_flags);1904	return file;1905}1906 1907struct file *io_file_get_normal(struct io_kiocb *req, int fd)1908{1909	struct file *file = fget(fd);1910 1911	trace_io_uring_file_get(req, fd);1912 1913	/* we don't allow fixed io_uring files */1914	if (file && io_is_uring_fops(file))1915		io_req_track_inflight(req);1916	return file;1917}1918 1919static HWJS_SUSPENDS void io_queue_async(struct io_kiocb *req, int ret)1920	__must_hold(&req->ctx->uring_lock)1921{1922	struct io_kiocb *linked_timeout;1923 1924	if (ret != -EAGAIN || (req->flags & REQ_F_NOWAIT)) {1925		io_req_defer_failed(req, ret);1926		return;1927	}1928 1929	linked_timeout = io_prep_linked_timeout(req);1930 1931	switch (io_arm_poll_handler(req, 0)) {1932	case IO_APOLL_READY:1933		io_kbuf_recycle(req, 0);1934		io_req_task_queue(req);1935		break;1936	case IO_APOLL_ABORTED:1937		io_kbuf_recycle(req, 0);1938		io_queue_iowq(req);1939		break;1940	case IO_APOLL_OK:1941		break;1942	}1943 1944	if (linked_timeout)1945		io_queue_linked_timeout(linked_timeout);1946}1947 1948static HWJS_SUSPENDS inline void io_queue_sqe(struct io_kiocb *req)1949	__must_hold(&req->ctx->uring_lock)1950{1951	int ret;1952 1953	ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);1954 1955	/*1956	 * We async punt it if the file wasn't marked NOWAIT, or if the file1957	 * doesn't support non-blocking read/write attempts1958	 */1959	if (unlikely(ret))1960		io_queue_async(req, ret);1961}1962 1963static HWJS_SUSPENDS void io_queue_sqe_fallback(struct io_kiocb *req)1964	__must_hold(&req->ctx->uring_lock)1965{1966	if (unlikely(req->flags & REQ_F_FAIL)) {1967		/*1968		 * We don't submit, fail them all, for that replace hardlinks1969		 * with normal links. Extra REQ_F_LINK is tolerated.1970		 */1971		req->flags &= ~REQ_F_HARDLINK;1972		req->flags |= REQ_F_LINK;1973		io_req_defer_failed(req, req->cqe.res);1974	} else {1975		if (unlikely(req->ctx->drain_active))1976			io_drain_req(req);1977		else1978			io_queue_iowq(req);1979	}1980}1981 1982/*1983 * Check SQE restrictions (opcode and flags).1984 *1985 * Returns 'true' if SQE is allowed, 'false' otherwise.1986 */1987static inline bool io_check_restriction(struct io_ring_ctx *ctx,1988					struct io_kiocb *req,1989					unsigned int sqe_flags)1990{1991	if (!test_bit(req->opcode, ctx->restrictions.sqe_op))1992		return false;1993 1994	if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=1995	    ctx->restrictions.sqe_flags_required)1996		return false;1997 1998	if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |1999			  ctx->restrictions.sqe_flags_required))2000		return false;2001 2002	return true;2003}2004 2005static void io_init_req_drain(struct io_kiocb *req)2006{2007	struct io_ring_ctx *ctx = req->ctx;2008	struct io_kiocb *head = ctx->submit_state.link.head;2009 2010	ctx->drain_active = true;2011	if (head) {2012		/*2013		 * If we need to drain a request in the middle of a link, drain2014		 * the head request and the next request/link after the current2015		 * link. Considering sequential execution of links,2016		 * REQ_F_IO_DRAIN will be maintained for every request of our2017		 * link.2018		 */2019		head->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;2020		ctx->drain_next = true;2021	}2022}2023 2024static __cold int io_init_fail_req(struct io_kiocb *req, int err)2025{2026	/* ensure per-opcode data is cleared if we fail before prep */2027	memset(&req->cmd.data, 0, sizeof(req->cmd.data));2028	return err;2029}2030 2031static HWJS_SUSPENDS int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,2032		       const struct io_uring_sqe *sqe)2033	__must_hold(&ctx->uring_lock)2034{2035	const struct io_issue_def *def;2036	unsigned int sqe_flags;2037	int personality;2038	u8 opcode;2039 2040	/* req is partially pre-initialised, see io_preinit_req() */2041	req->opcode = opcode = READ_ONCE(sqe->opcode);2042	/* same numerical values with corresponding REQ_F_*, safe to copy */2043	sqe_flags = READ_ONCE(sqe->flags);2044	req->flags = (__force io_req_flags_t) sqe_flags;2045	req->cqe.user_data = READ_ONCE(sqe->user_data);2046	req->file = NULL;2047	req->rsrc_node = NULL;2048	req->task = current;2049	req->cancel_seq_set = false;2050 2051	if (unlikely(opcode >= IORING_OP_LAST)) {2052		req->opcode = 0;2053		return io_init_fail_req(req, -EINVAL);2054	}2055	def = &io_issue_defs[opcode];2056	if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {2057		/* enforce forwards compatibility on users */2058		if (sqe_flags & ~SQE_VALID_FLAGS)2059			return io_init_fail_req(req, -EINVAL);2060		if (sqe_flags & IOSQE_BUFFER_SELECT) {2061			if (!def->buffer_select)2062				return io_init_fail_req(req, -EOPNOTSUPP);2063			req->buf_index = READ_ONCE(sqe->buf_group);2064		}2065		if (sqe_flags & IOSQE_CQE_SKIP_SUCCESS)2066			ctx->drain_disabled = true;2067		if (sqe_flags & IOSQE_IO_DRAIN) {2068			if (ctx->drain_disabled)2069				return io_init_fail_req(req, -EOPNOTSUPP);2070			io_init_req_drain(req);2071		}2072	}2073	if (unlikely(ctx->restricted || ctx->drain_active || ctx->drain_next)) {2074		if (ctx->restricted && !io_check_restriction(ctx, req, sqe_flags))2075			return io_init_fail_req(req, -EACCES);2076		/* knock it to the slow queue path, will be drained there */2077		if (ctx->drain_active)2078			req->flags |= REQ_F_FORCE_ASYNC;2079		/* if there is no link, we're at "next" request and need to drain */2080		if (unlikely(ctx->drain_next) && !ctx->submit_state.link.head) {2081			ctx->drain_next = false;2082			ctx->drain_active = true;2083			req->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;2084		}2085	}2086 2087	if (!def->ioprio && sqe->ioprio)2088		return io_init_fail_req(req, -EINVAL);2089	if (!def->iopoll && (ctx->flags & IORING_SETUP_IOPOLL))2090		return io_init_fail_req(req, -EINVAL);2091 2092	if (def->needs_file) {2093		struct io_submit_state *state = &ctx->submit_state;2094 2095		req->cqe.fd = READ_ONCE(sqe->fd);2096 2097		/*2098		 * Plug now if we have more than 2 IO left after this, and the2099		 * target is potentially a read/write to block based storage.2100		 */2101		if (state->need_plug && def->plug) {2102			state->plug_started = true;2103			state->need_plug = false;2104			blk_start_plug_nr_ios(&state->plug, state->submit_nr);2105		}2106	}2107 2108	personality = READ_ONCE(sqe->personality);2109	if (personality) {2110		int ret;2111 2112		req->creds = xa_load(&ctx->personalities, personality);2113		if (!req->creds)2114			return io_init_fail_req(req, -EINVAL);2115		get_cred(req->creds);2116		ret = security_uring_override_creds(req->creds);2117		if (ret) {2118			put_cred(req->creds);2119			return io_init_fail_req(req, ret);2120		}2121		req->flags |= REQ_F_CREDS;2122	}2123 2124	return def->prep(req, sqe);2125}2126 2127static HWJS_SUSPENDS __cold int io_submit_fail_init(const struct io_uring_sqe *sqe,2128				      struct io_kiocb *req, int ret)2129{2130	struct io_ring_ctx *ctx = req->ctx;2131	struct io_submit_link *link = &ctx->submit_state.link;2132	struct io_kiocb *head = link->head;2133 2134	trace_io_uring_req_failed(sqe, req, ret);2135 2136	/*2137	 * Avoid breaking links in the middle as it renders links with SQPOLL2138	 * unusable. Instead of failing eagerly, continue assembling the link if2139	 * applicable and mark the head with REQ_F_FAIL. The link flushing code2140	 * should find the flag and handle the rest.2141	 */2142	req_fail_link_node(req, ret);2143	if (head && !(head->flags & REQ_F_FAIL))2144		req_fail_link_node(head, -ECANCELED);2145 2146	if (!(req->flags & IO_REQ_LINK_FLAGS)) {2147		if (head) {2148			link->last->link = req;2149			link->head = NULL;2150			req = head;2151		}2152		io_queue_sqe_fallback(req);2153		return ret;2154	}2155 2156	if (head)2157		link->last->link = req;2158	else2159		link->head = req;2160	link->last = req;2161	return 0;2162}2163 2164static HWJS_SUSPENDS inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,2165			 const struct io_uring_sqe *sqe)2166	__must_hold(&ctx->uring_lock)2167{2168	struct io_submit_link *link = &ctx->submit_state.link;2169	int ret;2170 2171	ret = io_init_req(ctx, req, sqe);2172	if (unlikely(ret))2173		return io_submit_fail_init(sqe, req, ret);2174 2175	trace_io_uring_submit_req(req);2176 2177	/*2178	 * If we already have a head request, queue this one for async2179	 * submittal once the head completes. If we don't have a head but2180	 * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be2181	 * submitted sync once the chain is complete. If none of those2182	 * conditions are true (normal request), then just queue it.2183	 */2184	if (unlikely(link->head)) {2185		trace_io_uring_link(req, link->last);2186		link->last->link = req;2187		link->last = req;2188 2189		if (req->flags & IO_REQ_LINK_FLAGS)2190			return 0;2191		/* last request of the link, flush it */2192		req = link->head;2193		link->head = NULL;2194		if (req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL))2195			goto fallback;2196 2197	} else if (unlikely(req->flags & (IO_REQ_LINK_FLAGS |2198					  REQ_F_FORCE_ASYNC | REQ_F_FAIL))) {2199		if (req->flags & IO_REQ_LINK_FLAGS) {2200			link->head = req;2201			link->last = req;2202		} else {2203fallback:2204			io_queue_sqe_fallback(req);2205		}2206		return 0;2207	}2208 2209	io_queue_sqe(req);2210	return 0;2211}2212 2213/*2214 * Batched submission is done, ensure local IO is flushed out.2215 */2216static HWJS_SUSPENDS void io_submit_state_end(struct io_ring_ctx *ctx)2217{2218	struct io_submit_state *state = &ctx->submit_state;2219 2220	if (unlikely(state->link.head))2221		io_queue_sqe_fallback(state->link.head);2222	/* flush only after queuing links as they can generate completions */2223	io_submit_flush_completions(ctx);2224	if (state->plug_started)2225		blk_finish_plug(&state->plug);2226}2227 2228/*2229 * Start submission side cache.2230 */2231static void io_submit_state_start(struct io_submit_state *state,2232				  unsigned int max_ios)2233{2234	state->plug_started = false;2235	state->need_plug = max_ios > 2;2236	state->submit_nr = max_ios;2237	/* set only head, no need to init link_last in advance */2238	state->link.head = NULL;2239}2240 2241static void io_commit_sqring(struct io_ring_ctx *ctx)2242{2243	struct io_rings *rings = ctx->rings;2244 2245	/*2246	 * Ensure any loads from the SQEs are done at this point,2247	 * since once we write the new head, the application could2248	 * write new data to them.2249	 */2250	smp_store_release(&rings->sq.head, ctx->cached_sq_head);2251}2252 2253/*2254 * Fetch an sqe, if one is available. Note this returns a pointer to memory2255 * that is mapped by userspace. This means that care needs to be taken to2256 * ensure that reads are stable, as we cannot rely on userspace always2257 * being a good citizen. If members of the sqe are validated and then later2258 * used, it's important that those reads are done through READ_ONCE() to2259 * prevent a re-load down the line.2260 */2261static bool io_get_sqe(struct io_ring_ctx *ctx, const struct io_uring_sqe **sqe)2262{2263	unsigned mask = ctx->sq_entries - 1;2264	unsigned head = ctx->cached_sq_head++ & mask;2265 2266	if (!(ctx->flags & IORING_SETUP_NO_SQARRAY)) {2267		head = READ_ONCE(ctx->sq_array[head]);2268		if (unlikely(head >= ctx->sq_entries)) {2269			/* drop invalid entries */2270			spin_lock(&ctx->completion_lock);2271			ctx->cq_extra--;2272			spin_unlock(&ctx->completion_lock);2273			WRITE_ONCE(ctx->rings->sq_dropped,2274				   READ_ONCE(ctx->rings->sq_dropped) + 1);2275			return false;2276		}2277	}2278 2279	/*2280	 * The cached sq head (or cq tail) serves two purposes:2281	 *2282	 * 1) allows us to batch the cost of updating the user visible2283	 *    head updates.2284	 * 2) allows the kernel side to track the head on its own, even2285	 *    though the application is the one updating it.2286	 */2287 2288	/* double index for 128-byte SQEs, twice as long */2289	if (ctx->flags & IORING_SETUP_SQE128)2290		head <<= 1;2291	*sqe = &ctx->sq_sqes[head];2292	return true;2293}2294 2295int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)2296	__must_hold(&ctx->uring_lock)2297{2298	unsigned int entries = io_sqring_entries(ctx);2299	unsigned int left;2300	int ret;2301 2302	if (unlikely(!entries))2303		return 0;2304	/* make sure SQ entry isn't read before tail */2305	ret = left = min(nr, entries);2306	io_get_task_refs(left);2307	io_submit_state_start(&ctx->submit_state, left);2308 2309	do {2310		const struct io_uring_sqe *sqe;2311		struct io_kiocb *req;2312 2313		if (unlikely(!io_alloc_req(ctx, &req)))2314			break;2315		if (unlikely(!io_get_sqe(ctx, &sqe))) {2316			io_req_add_to_cache(req, ctx);2317			break;2318		}2319 2320		/*2321		 * Continue submitting even for sqe failure if the2322		 * ring was setup with IORING_SETUP_SUBMIT_ALL2323		 */2324		if (unlikely(io_submit_sqe(ctx, req, sqe)) &&2325		    !(ctx->flags & IORING_SETUP_SUBMIT_ALL)) {2326			left--;2327			break;2328		}2329	} while (--left);2330 2331	if (unlikely(left)) {2332		ret -= left;2333		/* try again if it submitted nothing and can't allocate a req */2334		if (!ret && io_req_cache_empty(ctx))2335			ret = -EAGAIN;2336		current->io_uring->cached_refs += left;2337	}2338 2339	io_submit_state_end(ctx);2340	 /* Commit SQ ring head once we've consumed and submitted all SQEs */2341	io_commit_sqring(ctx);2342	return ret;2343}2344 2345static HWJS_SUSPENDS int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,2346			    int wake_flags, void *key)2347{2348	struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq);2349 2350	/*2351	 * Cannot safely flush overflowed CQEs from here, ensure we wake up2352	 * the task, and the next invocation will do it.2353	 */2354	if (io_should_wake(iowq) || io_has_work(iowq->ctx))2355		return autoremove_wake_function(curr, mode, wake_flags, key);2356	return -1;2357}2358 2359int io_run_task_work_sig(struct io_ring_ctx *ctx)2360{2361	if (!llist_empty(&ctx->work_llist)) {2362		__set_current_state(TASK_RUNNING);2363		if (io_run_local_work(ctx, INT_MAX) > 0)2364			return 0;2365	}2366	if (io_run_task_work() > 0)2367		return 0;2368	if (task_sigpending(current))2369		return -EINTR;2370	return 0;2371}2372 2373static bool current_pending_io(void)2374{2375	struct io_uring_task *tctx = current->io_uring;2376 2377	if (!tctx)2378		return false;2379	return percpu_counter_read_positive(&tctx->inflight);2380}2381 2382static HWJS_SUSPENDS enum hrtimer_restart io_cqring_timer_wakeup(struct hrtimer *timer)2383{2384	struct io_wait_queue *iowq = container_of(timer, struct io_wait_queue, t);2385 2386	WRITE_ONCE(iowq->hit_timeout, 1);2387	iowq->min_timeout = 0;2388	wake_up_process(iowq->wq.private);2389	return HRTIMER_NORESTART;2390}2391 2392/*2393 * Doing min_timeout portion. If we saw any timeouts, events, or have work,2394 * wake up. If not, and we have a normal timeout, switch to that and keep2395 * sleeping.2396 */2397static HWJS_SUSPENDS enum hrtimer_restart io_cqring_min_timer_wakeup(struct hrtimer *timer)2398{2399	struct io_wait_queue *iowq = container_of(timer, struct io_wait_queue, t);2400	struct io_ring_ctx *ctx = iowq->ctx;2401 2402	/* no general timeout, or shorter (or equal), we are done */2403	if (iowq->timeout == KTIME_MAX ||2404	    ktime_compare(iowq->min_timeout, iowq->timeout) >= 0)2405		goto out_wake;2406	/* work we may need to run, wake function will see if we need to wake */2407	if (io_has_work(ctx))2408		goto out_wake;2409	/* got events since we started waiting, min timeout is done */2410	if (iowq->cq_min_tail != READ_ONCE(ctx->rings->cq.tail))2411		goto out_wake;2412	/* if we have any events and min timeout expired, we're done */2413	if (io_cqring_events(ctx))2414		goto out_wake;2415 2416	/*2417	 * If using deferred task_work running and application is waiting on2418	 * more than one request, ensure we reset it now where we are switching2419	 * to normal sleeps. Any request completion post min_wait should wake2420	 * the task and return.2421	 */2422	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {2423		atomic_set(&ctx->cq_wait_nr, 1);2424		smp_mb();2425		if (!llist_empty(&ctx->work_llist))2426			goto out_wake;2427	}2428 2429	iowq->t.function = io_cqring_timer_wakeup;2430	hrtimer_set_expires(timer, iowq->timeout);2431	return HRTIMER_RESTART;2432out_wake:2433	return io_cqring_timer_wakeup(timer);2434}2435 2436static HWJS_SUSPENDS int io_cqring_schedule_timeout(struct io_wait_queue *iowq,2437				      clockid_t clock_id, ktime_t start_time)2438{2439	ktime_t timeout;2440 2441	hrtimer_init_on_stack(&iowq->t, clock_id, HRTIMER_MODE_ABS);2442	if (iowq->min_timeout) {2443		timeout = ktime_add_ns(iowq->min_timeout, start_time);2444		iowq->t.function = io_cqring_min_timer_wakeup;2445	} else {2446		timeout = iowq->timeout;2447		iowq->t.function = io_cqring_timer_wakeup;2448	}2449 2450	hrtimer_set_expires_range_ns(&iowq->t, timeout, 0);2451	hrtimer_start_expires(&iowq->t, HRTIMER_MODE_ABS);2452 2453	if (!READ_ONCE(iowq->hit_timeout))2454		schedule();2455 2456	hrtimer_cancel(&iowq->t);2457	destroy_hrtimer_on_stack(&iowq->t);2458	__set_current_state(TASK_RUNNING);2459 2460	return READ_ONCE(iowq->hit_timeout) ? -ETIME : 0;2461}2462 2463static HWJS_SUSPENDS int __io_cqring_wait_schedule(struct io_ring_ctx *ctx,2464				     struct io_wait_queue *iowq,2465				     ktime_t start_time)2466{2467	int ret = 0;2468 2469	/*2470	 * Mark us as being in io_wait if we have pending requests, so cpufreq2471	 * can take into account that the task is waiting for IO - turns out2472	 * to be important for low QD IO.2473	 */2474	if (current_pending_io())2475		current->in_iowait = 1;2476	if (iowq->timeout != KTIME_MAX || iowq->min_timeout)2477		ret = io_cqring_schedule_timeout(iowq, ctx->clockid, start_time);2478	else2479		schedule();2480	current->in_iowait = 0;2481	return ret;2482}2483 2484/* If this returns > 0, the caller should retry */2485static HWJS_SUSPENDS inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,2486					  struct io_wait_queue *iowq,2487					  ktime_t start_time)2488{2489	if (unlikely(READ_ONCE(ctx->check_cq)))2490		return 1;2491	if (unlikely(!llist_empty(&ctx->work_llist)))2492		return 1;2493	if (unlikely(task_work_pending(current)))2494		return 1;2495	if (unlikely(task_sigpending(current)))2496		return -EINTR;2497	if (unlikely(io_should_wake(iowq)))2498		return 0;2499 2500	return __io_cqring_wait_schedule(ctx, iowq, start_time);2501}2502 2503struct ext_arg {2504	size_t argsz;2505	struct __kernel_timespec __user *ts;2506	const sigset_t __user *sig;2507	ktime_t min_time;2508};2509 2510/*2511 * Wait until events become available, if we don't already have some. The2512 * application must reap them itself, as they reside on the shared cq ring.2513 */2514static HWJS_SUSPENDS int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, u32 flags,2515			  struct ext_arg *ext_arg)2516{2517	struct io_wait_queue iowq;2518	struct io_rings *rings = ctx->rings;2519	ktime_t start_time;2520	int ret;2521 2522	if (!io_allowed_run_tw(ctx))2523		return -EEXIST;2524	if (!llist_empty(&ctx->work_llist))2525		io_run_local_work(ctx, min_events);2526	io_run_task_work();2527 2528	if (unlikely(test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)))2529		io_cqring_do_overflow_flush(ctx);2530	if (__io_cqring_events_user(ctx) >= min_events)2531		return 0;2532 2533	init_waitqueue_func_entry(&iowq.wq, io_wake_function);2534	iowq.wq.private = current;2535	INIT_LIST_HEAD(&iowq.wq.entry);2536	iowq.ctx = ctx;2537	iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;2538	iowq.cq_min_tail = READ_ONCE(ctx->rings->cq.tail);2539	iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);2540	iowq.hit_timeout = 0;2541	iowq.min_timeout = ext_arg->min_time;2542	iowq.timeout = KTIME_MAX;2543	start_time = io_get_time(ctx);2544 2545	if (ext_arg->ts) {2546		struct timespec64 ts;2547 2548		if (get_timespec64(&ts, ext_arg->ts))2549			return -EFAULT;2550 2551		iowq.timeout = timespec64_to_ktime(ts);2552		if (!(flags & IORING_ENTER_ABS_TIMER))2553			iowq.timeout = ktime_add(iowq.timeout, start_time);2554	}2555 2556	if (ext_arg->sig) {2557#ifdef CONFIG_COMPAT2558		if (in_compat_syscall())2559			ret = set_compat_user_sigmask((const compat_sigset_t __user *)ext_arg->sig,2560						      ext_arg->argsz);2561		else2562#endif2563			ret = set_user_sigmask(ext_arg->sig, ext_arg->argsz);2564 2565		if (ret)2566			return ret;2567	}2568 2569	io_napi_busy_loop(ctx, &iowq);2570 2571	trace_io_uring_cqring_wait(ctx, min_events);2572	do {2573		unsigned long check_cq;2574		int nr_wait;2575 2576		/* if min timeout has been hit, don't reset wait count */2577		if (!iowq.hit_timeout)2578			nr_wait = (int) iowq.cq_tail -2579					READ_ONCE(ctx->rings->cq.tail);2580		else2581			nr_wait = 1;2582 2583		if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {2584			atomic_set(&ctx->cq_wait_nr, nr_wait);2585			set_current_state(TASK_INTERRUPTIBLE);2586		} else {2587			prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,2588							TASK_INTERRUPTIBLE);2589		}2590 2591		ret = io_cqring_wait_schedule(ctx, &iowq, start_time);2592		__set_current_state(TASK_RUNNING);2593		atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT);2594 2595		/*2596		 * Run task_work after scheduling and before io_should_wake().2597		 * If we got woken because of task_work being processed, run it2598		 * now rather than let the caller do another wait loop.2599		 */2600		if (!llist_empty(&ctx->work_llist))2601			io_run_local_work(ctx, nr_wait);2602		io_run_task_work();2603 2604		/*2605		 * Non-local task_work will be run on exit to userspace, but2606		 * if we're using DEFER_TASKRUN, then we could have waited2607		 * with a timeout for a number of requests. If the timeout2608		 * hits, we could have some requests ready to process. Ensure2609		 * this break is _after_ we have run task_work, to avoid2610		 * deferring running potentially pending requests until the2611		 * next time we wait for events.2612		 */2613		if (ret < 0)2614			break;2615 2616		check_cq = READ_ONCE(ctx->check_cq);2617		if (unlikely(check_cq)) {2618			/* let the caller flush overflows, retry */2619			if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))2620				io_cqring_do_overflow_flush(ctx);2621			if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)) {2622				ret = -EBADR;2623				break;2624			}2625		}2626 2627		if (io_should_wake(&iowq)) {2628			ret = 0;2629			break;2630		}2631		cond_resched();2632	} while (1);2633 2634	if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))2635		finish_wait(&ctx->cq_wait, &iowq.wq);2636	restore_saved_sigmask_unless(ret == -EINTR);2637 2638	return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;2639}2640 2641static void *io_rings_map(struct io_ring_ctx *ctx, unsigned long uaddr,2642			  size_t size)2643{2644	return __io_uaddr_map(&ctx->ring_pages, &ctx->n_ring_pages, uaddr,2645				size);2646}2647 2648static void *io_sqes_map(struct io_ring_ctx *ctx, unsigned long uaddr,2649			 size_t size)2650{2651	return __io_uaddr_map(&ctx->sqe_pages, &ctx->n_sqe_pages, uaddr,2652				size);2653}2654 2655static HWJS_SUSPENDS void io_rings_free(struct io_ring_ctx *ctx)2656{2657	if (!(ctx->flags & IORING_SETUP_NO_MMAP)) {2658		io_pages_unmap(ctx->rings, &ctx->ring_pages, &ctx->n_ring_pages,2659				true);2660		io_pages_unmap(ctx->sq_sqes, &ctx->sqe_pages, &ctx->n_sqe_pages,2661				true);2662	} else {2663		io_pages_free(&ctx->ring_pages, ctx->n_ring_pages);2664		ctx->n_ring_pages = 0;2665		io_pages_free(&ctx->sqe_pages, ctx->n_sqe_pages);2666		ctx->n_sqe_pages = 0;2667		vunmap(ctx->rings);2668		vunmap(ctx->sq_sqes);2669	}2670 2671	ctx->rings = NULL;2672	ctx->sq_sqes = NULL;2673}2674 2675static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries,2676				unsigned int cq_entries, size_t *sq_offset)2677{2678	struct io_rings *rings;2679	size_t off, sq_array_size;2680 2681	off = struct_size(rings, cqes, cq_entries);2682	if (off == SIZE_MAX)2683		return SIZE_MAX;2684	if (ctx->flags & IORING_SETUP_CQE32) {2685		if (check_shl_overflow(off, 1, &off))2686			return SIZE_MAX;2687	}2688 2689#ifdef CONFIG_SMP2690	off = ALIGN(off, SMP_CACHE_BYTES);2691	if (off == 0)2692		return SIZE_MAX;2693#endif2694 2695	if (ctx->flags & IORING_SETUP_NO_SQARRAY) {2696		*sq_offset = SIZE_MAX;2697		return off;2698	}2699 2700	*sq_offset = off;2701 2702	sq_array_size = array_size(sizeof(u32), sq_entries);2703	if (sq_array_size == SIZE_MAX)2704		return SIZE_MAX;2705 2706	if (check_add_overflow(off, sq_array_size, &off))2707		return SIZE_MAX;2708 2709	return off;2710}2711 2712static HWJS_SUSPENDS void io_req_caches_free(struct io_ring_ctx *ctx)2713{2714	struct io_kiocb *req;2715	int nr = 0;2716 2717	mutex_lock(&ctx->uring_lock);2718 2719	while (!io_req_cache_empty(ctx)) {2720		req = io_extract_req(ctx);2721		kmem_cache_free(req_cachep, req);2722		nr++;2723	}2724	if (nr)2725		percpu_ref_put_many(&ctx->refs, nr);2726	mutex_unlock(&ctx->uring_lock);2727}2728 2729static HWJS_SUSPENDS __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)2730{2731	io_sq_thread_finish(ctx);2732	/* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */2733	if (WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list)))2734		return;2735 2736	mutex_lock(&ctx->uring_lock);2737	if (ctx->buf_data)2738		__io_sqe_buffers_unregister(ctx);2739	if (ctx->file_data)2740		__io_sqe_files_unregister(ctx);2741	io_cqring_overflow_kill(ctx);2742	io_eventfd_unregister(ctx);2743	io_alloc_cache_free(&ctx->apoll_cache, kfree);2744	io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free);2745	io_alloc_cache_free(&ctx->rw_cache, io_rw_cache_free);2746	io_alloc_cache_free(&ctx->uring_cache, kfree);2747	io_alloc_cache_free(&ctx->msg_cache, io_msg_cache_free);2748	io_futex_cache_free(ctx);2749	io_destroy_buffers(ctx);2750	mutex_unlock(&ctx->uring_lock);2751	if (ctx->sq_creds)2752		put_cred(ctx->sq_creds);2753	if (ctx->submitter_task)2754		put_task_struct(ctx->submitter_task);2755 2756	/* there are no registered resources left, nobody uses it */2757	if (ctx->rsrc_node)2758		io_rsrc_node_destroy(ctx, ctx->rsrc_node);2759 2760	WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list));2761	WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list));2762 2763	io_alloc_cache_free(&ctx->rsrc_node_cache, kfree);2764	if (ctx->mm_account) {2765		mmdrop(ctx->mm_account);2766		ctx->mm_account = NULL;2767	}2768	io_rings_free(ctx);2769 2770	percpu_ref_exit(&ctx->refs);2771	free_uid(ctx->user);2772	io_req_caches_free(ctx);2773	if (ctx->hash_map)2774		io_wq_put_hash(ctx->hash_map);2775	io_napi_free(ctx);2776	kfree(ctx->cancel_table.hbs);2777	kfree(ctx->cancel_table_locked.hbs);2778	xa_destroy(&ctx->io_bl_xa);2779	kfree(ctx);2780}2781 2782static HWJS_SUSPENDS __cold void io_activate_pollwq_cb(struct callback_head *cb)2783{2784	struct io_ring_ctx *ctx = container_of(cb, struct io_ring_ctx,2785					       poll_wq_task_work);2786 2787	mutex_lock(&ctx->uring_lock);2788	ctx->poll_activated = true;2789	mutex_unlock(&ctx->uring_lock);2790 2791	/*2792	 * Wake ups for some events between start of polling and activation2793	 * might've been lost due to loose synchronisation.2794	 */2795	wake_up_all(&ctx->poll_wq);2796	percpu_ref_put(&ctx->refs);2797}2798 2799__cold void io_activate_pollwq(struct io_ring_ctx *ctx)2800{2801	spin_lock(&ctx->completion_lock);2802	/* already activated or in progress */2803	if (ctx->poll_activated || ctx->poll_wq_task_work.func)2804		goto out;2805	if (WARN_ON_ONCE(!ctx->task_complete))2806		goto out;2807	if (!ctx->submitter_task)2808		goto out;2809	/*2810	 * with ->submitter_task only the submitter task completes requests, we2811	 * only need to sync with it, which is done by injecting a tw2812	 */2813	init_task_work(&ctx->poll_wq_task_work, io_activate_pollwq_cb);2814	percpu_ref_get(&ctx->refs);2815	if (task_work_add(ctx->submitter_task, &ctx->poll_wq_task_work, TWA_SIGNAL))2816		percpu_ref_put(&ctx->refs);2817out:2818	spin_unlock(&ctx->completion_lock);2819}2820 2821static HWJS_SUSPENDS __poll_t io_uring_poll(struct file *file, poll_table *wait)2822{2823	struct io_ring_ctx *ctx = file->private_data;2824	__poll_t mask = 0;2825 2826	if (unlikely(!ctx->poll_activated))2827		io_activate_pollwq(ctx);2828 2829	poll_wait(file, &ctx->poll_wq, wait);2830	/*2831	 * synchronizes with barrier from wq_has_sleeper call in2832	 * io_commit_cqring2833	 */2834	smp_rmb();2835	if (!io_sqring_full(ctx))2836		mask |= EPOLLOUT | EPOLLWRNORM;2837 2838	/*2839	 * Don't flush cqring overflow list here, just do a simple check.2840	 * Otherwise there could possible be ABBA deadlock:2841	 *      CPU0                    CPU12842	 *      ----                    ----2843	 * lock(&ctx->uring_lock);2844	 *                              lock(&ep->mtx);2845	 *                              lock(&ctx->uring_lock);2846	 * lock(&ep->mtx);2847	 *2848	 * Users may get EPOLLIN meanwhile seeing nothing in cqring, this2849	 * pushes them to do the flush.2850	 */2851 2852	if (__io_cqring_events_user(ctx) || io_has_work(ctx))2853		mask |= EPOLLIN | EPOLLRDNORM;2854 2855	return mask;2856}2857 2858struct io_tctx_exit {2859	struct callback_head		task_work;2860	struct completion		completion;2861	struct io_ring_ctx		*ctx;2862};2863 2864static HWJS_SUSPENDS __cold void io_tctx_exit_cb(struct callback_head *cb)2865{2866	struct io_uring_task *tctx = current->io_uring;2867	struct io_tctx_exit *work;2868 2869	work = container_of(cb, struct io_tctx_exit, task_work);2870	/*2871	 * When @in_cancel, we're in cancellation and it's racy to remove the2872	 * node. It'll be removed by the end of cancellation, just ignore it.2873	 * tctx can be NULL if the queueing of this task_work raced with2874	 * work cancelation off the exec path.2875	 */2876	if (tctx && !atomic_read(&tctx->in_cancel))2877		io_uring_del_tctx_node((unsigned long)work->ctx);2878	complete(&work->completion);2879}2880 2881static __cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)2882{2883	struct io_kiocb *req = container_of(work, struct io_kiocb, work);2884 2885	return req->ctx == data;2886}2887 2888static HWJS_SUSPENDS __cold void io_ring_exit_work(struct work_struct *work)2889{2890	struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work);2891	unsigned long timeout = jiffies + HZ * 60 * 5;2892	unsigned long interval = HZ / 20;2893	struct io_tctx_exit exit;2894	struct io_tctx_node *node;2895	int ret;2896 2897	/*2898	 * If we're doing polled IO and end up having requests being2899	 * submitted async (out-of-line), then completions can come in while2900	 * we're waiting for refs to drop. We need to reap these manually,2901	 * as nobody else will be looking for them.2902	 */2903	do {2904		if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) {2905			mutex_lock(&ctx->uring_lock);2906			io_cqring_overflow_kill(ctx);2907			mutex_unlock(&ctx->uring_lock);2908		}2909 2910		if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)2911			io_move_task_work_from_local(ctx);2912 2913		while (io_uring_try_cancel_requests(ctx, NULL, true))2914			cond_resched();2915 2916		if (ctx->sq_data) {2917			struct io_sq_data *sqd = ctx->sq_data;2918			struct task_struct *tsk;2919 2920			io_sq_thread_park(sqd);2921			tsk = sqd->thread;2922			if (tsk && tsk->io_uring && tsk->io_uring->io_wq)2923				io_wq_cancel_cb(tsk->io_uring->io_wq,2924						io_cancel_ctx_cb, ctx, true);2925			io_sq_thread_unpark(sqd);2926		}2927 2928		io_req_caches_free(ctx);2929 2930		if (WARN_ON_ONCE(time_after(jiffies, timeout))) {2931			/* there is little hope left, don't run it too often */2932			interval = HZ * 60;2933		}2934		/*2935		 * This is really an uninterruptible wait, as it has to be2936		 * complete. But it's also run from a kworker, which doesn't2937		 * take signals, so it's fine to make it interruptible. This2938		 * avoids scenarios where we knowingly can wait much longer2939		 * on completions, for example if someone does a SIGSTOP on2940		 * a task that needs to finish task_work to make this loop2941		 * complete. That's a synthetic situation that should not2942		 * cause a stuck task backtrace, and hence a potential panic2943		 * on stuck tasks if that is enabled.2944		 */2945	} while (!wait_for_completion_interruptible_timeout(&ctx->ref_comp, interval));2946 2947	init_completion(&exit.completion);2948	init_task_work(&exit.task_work, io_tctx_exit_cb);2949	exit.ctx = ctx;2950 2951	mutex_lock(&ctx->uring_lock);2952	while (!list_empty(&ctx->tctx_list)) {2953		WARN_ON_ONCE(time_after(jiffies, timeout));2954 2955		node = list_first_entry(&ctx->tctx_list, struct io_tctx_node,2956					ctx_node);2957		/* don't spin on a single task if cancellation failed */2958		list_rotate_left(&ctx->tctx_list);2959		ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL);2960		if (WARN_ON_ONCE(ret))2961			continue;2962 2963		mutex_unlock(&ctx->uring_lock);2964		/*2965		 * See comment above for2966		 * wait_for_completion_interruptible_timeout() on why this2967		 * wait is marked as interruptible.2968		 */2969		wait_for_completion_interruptible(&exit.completion);2970		mutex_lock(&ctx->uring_lock);2971	}2972	mutex_unlock(&ctx->uring_lock);2973	spin_lock(&ctx->completion_lock);2974	spin_unlock(&ctx->completion_lock);2975 2976	/* pairs with RCU read section in io_req_local_work_add() */2977	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)2978		synchronize_rcu();2979 2980	io_ring_ctx_free(ctx);2981}2982 2983static HWJS_SUSPENDS __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)2984{2985	unsigned long index;2986	struct creds *creds;2987 2988	mutex_lock(&ctx->uring_lock);2989	percpu_ref_kill(&ctx->refs);2990	xa_for_each(&ctx->personalities, index, creds)2991		io_unregister_personality(ctx, index);2992	mutex_unlock(&ctx->uring_lock);2993 2994	flush_delayed_work(&ctx->fallback_work);2995 2996	INIT_WORK(&ctx->exit_work, io_ring_exit_work);2997	/*2998	 * Use system_unbound_wq to avoid spawning tons of event kworkers2999	 * if we're exiting a ton of rings at the same time. It just adds3000	 * noise and overhead, there's no discernable change in runtime3001	 * over using system_wq.3002	 */3003	queue_work(iou_wq, &ctx->exit_work);3004}3005 3006static HWJS_SUSPENDS int io_uring_release(struct inode *inode, struct file *file)3007{3008	struct io_ring_ctx *ctx = file->private_data;3009 3010	file->private_data = NULL;3011	io_ring_ctx_wait_and_kill(ctx);3012	return 0;3013}3014 3015struct io_task_cancel {3016	struct task_struct *task;3017	bool all;3018};3019 3020static bool io_cancel_task_cb(struct io_wq_work *work, void *data)3021{3022	struct io_kiocb *req = container_of(work, struct io_kiocb, work);3023	struct io_task_cancel *cancel = data;3024 3025	return io_match_task_safe(req, cancel->task, cancel->all);3026}3027 3028static HWJS_SUSPENDS __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,3029					 struct task_struct *task,3030					 bool cancel_all)3031{3032	struct io_defer_entry *de;3033	LIST_HEAD(list);3034 3035	spin_lock(&ctx->completion_lock);3036	list_for_each_entry_reverse(de, &ctx->defer_list, list) {3037		if (io_match_task_safe(de->req, task, cancel_all)) {3038			list_cut_position(&list, &ctx->defer_list, &de->list);3039			break;3040		}3041	}3042	spin_unlock(&ctx->completion_lock);3043	if (list_empty(&list))3044		return false;3045 3046	while (!list_empty(&list)) {3047		de = list_first_entry(&list, struct io_defer_entry, list);3048		list_del_init(&de->list);3049		io_req_task_queue_fail(de->req, -ECANCELED);3050		kfree(de);3051	}3052	return true;3053}3054 3055static HWJS_SUSPENDS __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx)3056{3057	struct io_tctx_node *node;3058	enum io_wq_cancel cret;3059	bool ret = false;3060 3061	mutex_lock(&ctx->uring_lock);3062	list_for_each_entry(node, &ctx->tctx_list, ctx_node) {3063		struct io_uring_task *tctx = node->task->io_uring;3064 3065		/*3066		 * io_wq will stay alive while we hold uring_lock, because it's3067		 * killed after ctx nodes, which requires to take the lock.3068		 */3069		if (!tctx || !tctx->io_wq)3070			continue;3071		cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true);3072		ret |= (cret != IO_WQ_CANCEL_NOTFOUND);3073	}3074	mutex_unlock(&ctx->uring_lock);3075 3076	return ret;3077}3078 3079static HWJS_SUSPENDS __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,3080						struct task_struct *task,3081						bool cancel_all)3082{3083	struct io_task_cancel cancel = { .task = task, .all = cancel_all, };3084	struct io_uring_task *tctx = task ? task->io_uring : NULL;3085	enum io_wq_cancel cret;3086	bool ret = false;3087 3088	/* set it so io_req_local_work_add() would wake us up */3089	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {3090		atomic_set(&ctx->cq_wait_nr, 1);3091		smp_mb();3092	}3093 3094	/* failed during ring init, it couldn't have issued any requests */3095	if (!ctx->rings)3096		return false;3097 3098	if (!task) {3099		ret |= io_uring_try_cancel_iowq(ctx);3100	} else if (tctx && tctx->io_wq) {3101		/*3102		 * Cancels requests of all rings, not only @ctx, but3103		 * it's fine as the task is in exit/exec.3104		 */3105		cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb,3106				       &cancel, true);3107		ret |= (cret != IO_WQ_CANCEL_NOTFOUND);3108	}3109 3110	/* SQPOLL thread does its own polling */3111	if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) ||3112	    (ctx->sq_data && ctx->sq_data->thread == current)) {3113		while (!wq_list_empty(&ctx->iopoll_list)) {3114			io_iopoll_try_reap_events(ctx);3115			ret = true;3116			cond_resched();3117		}3118	}3119 3120	if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&3121	    io_allowed_defer_tw_run(ctx))3122		ret |= io_run_local_work(ctx, INT_MAX) > 0;3123	ret |= io_cancel_defer_files(ctx, task, cancel_all);3124	mutex_lock(&ctx->uring_lock);3125	ret |= io_poll_remove_all(ctx, task, cancel_all);3126	ret |= io_waitid_remove_all(ctx, task, cancel_all);3127	ret |= io_futex_remove_all(ctx, task, cancel_all);3128	ret |= io_uring_try_cancel_uring_cmd(ctx, task, cancel_all);3129	mutex_unlock(&ctx->uring_lock);3130	ret |= io_kill_timeouts(ctx, task, cancel_all);3131	if (task)3132		ret |= io_run_task_work() > 0;3133	else3134		ret |= flush_delayed_work(&ctx->fallback_work);3135	return ret;3136}3137 3138static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)3139{3140	if (tracked)3141		return atomic_read(&tctx->inflight_tracked);3142	return percpu_counter_sum(&tctx->inflight);3143}3144 3145/*3146 * Find any io_uring ctx that this task has registered or done IO on, and cancel3147 * requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation.3148 */3149__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd)3150{3151	struct io_uring_task *tctx = current->io_uring;3152	struct io_ring_ctx *ctx;3153	struct io_tctx_node *node;3154	unsigned long index;3155	s64 inflight;3156	DEFINE_WAIT(wait);3157 3158	WARN_ON_ONCE(sqd && sqd->thread != current);3159 3160	if (!current->io_uring)3161		return;3162	if (tctx->io_wq)3163		io_wq_exit_start(tctx->io_wq);3164 3165	atomic_inc(&tctx->in_cancel);3166	do {3167		bool loop = false;3168 3169		io_uring_drop_tctx_refs(current);3170		if (!tctx_inflight(tctx, !cancel_all))3171			break;3172 3173		/* read completions before cancelations */3174		inflight = tctx_inflight(tctx, false);3175		if (!inflight)3176			break;3177 3178		if (!sqd) {3179			xa_for_each(&tctx->xa, index, node) {3180				/* sqpoll task will cancel all its requests */3181				if (node->ctx->sq_data)3182					continue;3183				loop |= io_uring_try_cancel_requests(node->ctx,3184							current, cancel_all);3185			}3186		} else {3187			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)3188				loop |= io_uring_try_cancel_requests(ctx,3189								     current,3190								     cancel_all);3191		}3192 3193		if (loop) {3194			cond_resched();3195			continue;3196		}3197 3198		prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE);3199		io_run_task_work();3200		io_uring_drop_tctx_refs(current);3201		xa_for_each(&tctx->xa, index, node) {3202			if (!llist_empty(&node->ctx->work_llist)) {3203				WARN_ON_ONCE(node->ctx->submitter_task &&3204					     node->ctx->submitter_task != current);3205				goto end_wait;3206			}3207		}3208		/*3209		 * If we've seen completions, retry without waiting. This3210		 * avoids a race where a completion comes in before we did3211		 * prepare_to_wait().3212		 */3213		if (inflight == tctx_inflight(tctx, !cancel_all))3214			schedule();3215end_wait:3216		finish_wait(&tctx->wait, &wait);3217	} while (1);3218 3219	io_uring_clean_tctx(tctx);3220	if (cancel_all) {3221		/*3222		 * We shouldn't run task_works after cancel, so just leave3223		 * ->in_cancel set for normal exit.3224		 */3225		atomic_dec(&tctx->in_cancel);3226		/* for exec all current's requests should be gone, kill tctx */3227		__io_uring_free(current);3228	}3229}3230 3231void __io_uring_cancel(bool cancel_all)3232{3233	io_uring_cancel_generic(cancel_all, NULL);3234}3235 3236static int io_validate_ext_arg(unsigned flags, const void __user *argp, size_t argsz)3237{3238	if (flags & IORING_ENTER_EXT_ARG) {3239		struct io_uring_getevents_arg arg;3240 3241		if (argsz != sizeof(arg))3242			return -EINVAL;3243		if (copy_from_user(&arg, argp, sizeof(arg)))3244			return -EFAULT;3245	}3246	return 0;3247}3248 3249static int io_get_ext_arg(unsigned flags, const void __user *argp,3250			  struct ext_arg *ext_arg)3251{3252	struct io_uring_getevents_arg arg;3253 3254	/*3255	 * If EXT_ARG isn't set, then we have no timespec and the argp pointer3256	 * is just a pointer to the sigset_t.3257	 */3258	if (!(flags & IORING_ENTER_EXT_ARG)) {3259		ext_arg->sig = (const sigset_t __user *) argp;3260		ext_arg->ts = NULL;3261		return 0;3262	}3263 3264	/*3265	 * EXT_ARG is set - ensure we agree on the size of it and copy in our3266	 * timespec and sigset_t pointers if good.3267	 */3268	if (ext_arg->argsz != sizeof(arg))3269		return -EINVAL;3270	if (copy_from_user(&arg, argp, sizeof(arg)))3271		return -EFAULT;3272	ext_arg->min_time = arg.min_wait_usec * NSEC_PER_USEC;3273	ext_arg->sig = u64_to_user_ptr(arg.sigmask);3274	ext_arg->argsz = arg.sigmask_sz;3275	ext_arg->ts = u64_to_user_ptr(arg.ts);3276	return 0;3277}3278 3279SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,3280		u32, min_complete, u32, flags, const void __user *, argp,3281		size_t, argsz)3282{3283	struct io_ring_ctx *ctx;3284	struct file *file;3285	long ret;3286 3287	if (unlikely(flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP |3288			       IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG |3289			       IORING_ENTER_REGISTERED_RING |3290			       IORING_ENTER_ABS_TIMER)))3291		return -EINVAL;3292 3293	/*3294	 * Ring fd has been registered via IORING_REGISTER_RING_FDS, we3295	 * need only dereference our task private array to find it.3296	 */3297	if (flags & IORING_ENTER_REGISTERED_RING) {3298		struct io_uring_task *tctx = current->io_uring;3299 3300		if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX))3301			return -EINVAL;3302		fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);3303		file = tctx->registered_rings[fd];3304		if (unlikely(!file))3305			return -EBADF;3306	} else {3307		file = fget(fd);3308		if (unlikely(!file))3309			return -EBADF;3310		ret = -EOPNOTSUPP;3311		if (unlikely(!io_is_uring_fops(file)))3312			goto out;3313	}3314 3315	ctx = file->private_data;3316	ret = -EBADFD;3317	if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED))3318		goto out;3319 3320	/*3321	 * For SQ polling, the thread will do all submissions and completions.3322	 * Just return the requested submit count, and wake the thread if3323	 * we were asked to.3324	 */3325	ret = 0;3326	if (ctx->flags & IORING_SETUP_SQPOLL) {3327		if (unlikely(ctx->sq_data->thread == NULL)) {3328			ret = -EOWNERDEAD;3329			goto out;3330		}3331		if (flags & IORING_ENTER_SQ_WAKEUP)3332			wake_up(&ctx->sq_data->wait);3333		if (flags & IORING_ENTER_SQ_WAIT)3334			io_sqpoll_wait_sq(ctx);3335 3336		ret = to_submit;3337	} else if (to_submit) {3338		ret = io_uring_add_tctx_node(ctx);3339		if (unlikely(ret))3340			goto out;3341 3342		mutex_lock(&ctx->uring_lock);3343		ret = io_submit_sqes(ctx, to_submit);3344		if (ret != to_submit) {3345			mutex_unlock(&ctx->uring_lock);3346			goto out;3347		}3348		if (flags & IORING_ENTER_GETEVENTS) {3349			if (ctx->syscall_iopoll)3350				goto iopoll_locked;3351			/*3352			 * Ignore errors, we'll soon call io_cqring_wait() and3353			 * it should handle ownership problems if any.3354			 */3355			if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)3356				(void)io_run_local_work_locked(ctx, min_complete);3357		}3358		mutex_unlock(&ctx->uring_lock);3359	}3360 3361	if (flags & IORING_ENTER_GETEVENTS) {3362		int ret2;3363 3364		if (ctx->syscall_iopoll) {3365			/*3366			 * We disallow the app entering submit/complete with3367			 * polling, but we still need to lock the ring to3368			 * prevent racing with polled issue that got punted to3369			 * a workqueue.3370			 */3371			mutex_lock(&ctx->uring_lock);3372iopoll_locked:3373			ret2 = io_validate_ext_arg(flags, argp, argsz);3374			if (likely(!ret2)) {3375				min_complete = min(min_complete,3376						   ctx->cq_entries);3377				ret2 = io_iopoll_check(ctx, min_complete);3378			}3379			mutex_unlock(&ctx->uring_lock);3380		} else {3381			struct ext_arg ext_arg = { .argsz = argsz };3382 3383			ret2 = io_get_ext_arg(flags, argp, &ext_arg);3384			if (likely(!ret2)) {3385				min_complete = min(min_complete,3386						   ctx->cq_entries);3387				ret2 = io_cqring_wait(ctx, min_complete, flags,3388						      &ext_arg);3389			}3390		}3391 3392		if (!ret) {3393			ret = ret2;3394 3395			/*3396			 * EBADR indicates that one or more CQE were dropped.3397			 * Once the user has been informed we can clear the bit3398			 * as they are obviously ok with those drops.3399			 */3400			if (unlikely(ret2 == -EBADR))3401				clear_bit(IO_CHECK_CQ_DROPPED_BIT,3402					  &ctx->check_cq);3403		}3404	}3405out:3406	if (!(flags & IORING_ENTER_REGISTERED_RING))3407		fput(file);3408	return ret;3409}3410 3411static const struct file_operations io_uring_fops = {3412	.release	= io_uring_release,3413	.mmap		= io_uring_mmap,3414	.get_unmapped_area = io_uring_get_unmapped_area,3415#ifndef CONFIG_MMU3416	.mmap_capabilities = io_uring_nommu_mmap_capabilities,3417#endif3418	.poll		= io_uring_poll,3419#ifdef CONFIG_PROC_FS3420	.show_fdinfo	= io_uring_show_fdinfo,3421#endif3422};3423 3424bool io_is_uring_fops(struct file *file)3425{3426	return file->f_op == &io_uring_fops;3427}3428 3429static HWJS_SUSPENDS __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,3430					 struct io_uring_params *p)3431{3432	struct io_rings *rings;3433	size_t size, sq_array_offset;3434	void *ptr;3435 3436	/* make sure these are sane, as we already accounted them */3437	ctx->sq_entries = p->sq_entries;3438	ctx->cq_entries = p->cq_entries;3439 3440	size = rings_size(ctx, p->sq_entries, p->cq_entries, &sq_array_offset);3441	if (size == SIZE_MAX)3442		return -EOVERFLOW;3443 3444	if (!(ctx->flags & IORING_SETUP_NO_MMAP))3445		rings = io_pages_map(&ctx->ring_pages, &ctx->n_ring_pages, size);3446	else3447		rings = io_rings_map(ctx, p->cq_off.user_addr, size);3448 3449	if (IS_ERR(rings))3450		return PTR_ERR(rings);3451 3452	ctx->rings = rings;3453	if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))3454		ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);3455	rings->sq_ring_mask = p->sq_entries - 1;3456	rings->cq_ring_mask = p->cq_entries - 1;3457	rings->sq_ring_entries = p->sq_entries;3458	rings->cq_ring_entries = p->cq_entries;3459 3460	if (p->flags & IORING_SETUP_SQE128)3461		size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries);3462	else3463		size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);3464	if (size == SIZE_MAX) {3465		io_rings_free(ctx);3466		return -EOVERFLOW;3467	}3468 3469	if (!(ctx->flags & IORING_SETUP_NO_MMAP))3470		ptr = io_pages_map(&ctx->sqe_pages, &ctx->n_sqe_pages, size);3471	else3472		ptr = io_sqes_map(ctx, p->sq_off.user_addr, size);3473 3474	if (IS_ERR(ptr)) {3475		io_rings_free(ctx);3476		return PTR_ERR(ptr);3477	}3478 3479	ctx->sq_sqes = ptr;3480	return 0;3481}3482 3483static HWJS_SUSPENDS int io_uring_install_fd(struct file *file)3484{3485	int fd;3486 3487	fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);3488	if (fd < 0)3489		return fd;3490	fd_install(fd, file);3491	return fd;3492}3493 3494/*3495 * Allocate an anonymous fd, this is what constitutes the application3496 * visible backing of an io_uring instance. The application mmaps this3497 * fd to gain access to the SQ/CQ ring details.3498 */3499static struct file *io_uring_get_file(struct io_ring_ctx *ctx)3500{3501	/* Create a new inode so that the LSM can block the creation.  */3502	return anon_inode_create_getfile("[io_uring]", &io_uring_fops, ctx,3503					 O_RDWR | O_CLOEXEC, NULL);3504}3505 3506static HWJS_SUSPENDS __cold int io_uring_create(unsigned entries, struct io_uring_params *p,3507				  struct io_uring_params __user *params)3508{3509	struct io_ring_ctx *ctx;3510	struct io_uring_task *tctx;3511	struct file *file;3512	int ret;3513 3514	if (!entries)3515		return -EINVAL;3516	if (entries > IORING_MAX_ENTRIES) {3517		if (!(p->flags & IORING_SETUP_CLAMP))3518			return -EINVAL;3519		entries = IORING_MAX_ENTRIES;3520	}3521 3522	if ((p->flags & IORING_SETUP_REGISTERED_FD_ONLY)3523	    && !(p->flags & IORING_SETUP_NO_MMAP))3524		return -EINVAL;3525 3526	/*3527	 * Use twice as many entries for the CQ ring. It's possible for the3528	 * application to drive a higher depth than the size of the SQ ring,3529	 * since the sqes are only used at submission time. This allows for3530	 * some flexibility in overcommitting a bit. If the application has3531	 * set IORING_SETUP_CQSIZE, it will have passed in the desired number3532	 * of CQ ring entries manually.3533	 */3534	p->sq_entries = roundup_pow_of_two(entries);3535	if (p->flags & IORING_SETUP_CQSIZE) {3536		/*3537		 * If IORING_SETUP_CQSIZE is set, we do the same roundup3538		 * to a power-of-two, if it isn't already. We do NOT impose3539		 * any cq vs sq ring sizing.3540		 */3541		if (!p->cq_entries)3542			return -EINVAL;3543		if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {3544			if (!(p->flags & IORING_SETUP_CLAMP))3545				return -EINVAL;3546			p->cq_entries = IORING_MAX_CQ_ENTRIES;3547		}3548		p->cq_entries = roundup_pow_of_two(p->cq_entries);3549		if (p->cq_entries < p->sq_entries)3550			return -EINVAL;3551	} else {3552		p->cq_entries = 2 * p->sq_entries;3553	}3554 3555	ctx = io_ring_ctx_alloc(p);3556	if (!ctx)3557		return -ENOMEM;3558 3559	ctx->clockid = CLOCK_MONOTONIC;3560	ctx->clock_offset = 0;3561 3562	if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&3563	    !(ctx->flags & IORING_SETUP_IOPOLL) &&3564	    !(ctx->flags & IORING_SETUP_SQPOLL))3565		ctx->task_complete = true;3566 3567	if (ctx->task_complete || (ctx->flags & IORING_SETUP_IOPOLL))3568		ctx->lockless_cq = true;3569 3570	/*3571	 * lazy poll_wq activation relies on ->task_complete for synchronisation3572	 * purposes, see io_activate_pollwq()3573	 */3574	if (!ctx->task_complete)3575		ctx->poll_activated = true;3576 3577	/*3578	 * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user3579	 * space applications don't need to do io completion events3580	 * polling again, they can rely on io_sq_thread to do polling3581	 * work, which can reduce cpu usage and uring_lock contention.3582	 */3583	if (ctx->flags & IORING_SETUP_IOPOLL &&3584	    !(ctx->flags & IORING_SETUP_SQPOLL))3585		ctx->syscall_iopoll = 1;3586 3587	ctx->compat = in_compat_syscall();3588	if (!ns_capable_noaudit(&init_user_ns, CAP_IPC_LOCK))3589		ctx->user = get_uid(current_user());3590 3591	/*3592	 * For SQPOLL, we just need a wakeup, always. For !SQPOLL, if3593	 * COOP_TASKRUN is set, then IPIs are never needed by the app.3594	 */3595	ret = -EINVAL;3596	if (ctx->flags & IORING_SETUP_SQPOLL) {3597		/* IPI related flags don't make sense with SQPOLL */3598		if (ctx->flags & (IORING_SETUP_COOP_TASKRUN |3599				  IORING_SETUP_TASKRUN_FLAG |3600				  IORING_SETUP_DEFER_TASKRUN))3601			goto err;3602		ctx->notify_method = TWA_SIGNAL_NO_IPI;3603	} else if (ctx->flags & IORING_SETUP_COOP_TASKRUN) {3604		ctx->notify_method = TWA_SIGNAL_NO_IPI;3605	} else {3606		if (ctx->flags & IORING_SETUP_TASKRUN_FLAG &&3607		    !(ctx->flags & IORING_SETUP_DEFER_TASKRUN))3608			goto err;3609		ctx->notify_method = TWA_SIGNAL;3610	}3611 3612	/*3613	 * For DEFER_TASKRUN we require the completion task to be the same as the3614	 * submission task. This implies that there is only one submitter, so enforce3615	 * that.3616	 */3617	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN &&3618	    !(ctx->flags & IORING_SETUP_SINGLE_ISSUER)) {3619		goto err;3620	}3621 3622	/*3623	 * This is just grabbed for accounting purposes. When a process exits,3624	 * the mm is exited and dropped before the files, hence we need to hang3625	 * on to this mm purely for the purposes of being able to unaccount3626	 * memory (locked/pinned vm). It's not used for anything else.3627	 */3628	mmgrab(current->mm);3629	ctx->mm_account = current->mm;3630 3631	ret = io_allocate_scq_urings(ctx, p);3632	if (ret)3633		goto err;3634 3635	ret = io_sq_offload_create(ctx, p);3636	if (ret)3637		goto err;3638 3639	ret = io_rsrc_init(ctx);3640	if (ret)3641		goto err;3642 3643	p->sq_off.head = offsetof(struct io_rings, sq.head);3644	p->sq_off.tail = offsetof(struct io_rings, sq.tail);3645	p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);3646	p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);3647	p->sq_off.flags = offsetof(struct io_rings, sq_flags);3648	p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);3649	if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))3650		p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;3651	p->sq_off.resv1 = 0;3652	if (!(ctx->flags & IORING_SETUP_NO_MMAP))3653		p->sq_off.user_addr = 0;3654 3655	p->cq_off.head = offsetof(struct io_rings, cq.head);3656	p->cq_off.tail = offsetof(struct io_rings, cq.tail);3657	p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);3658	p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);3659	p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);3660	p->cq_off.cqes = offsetof(struct io_rings, cqes);3661	p->cq_off.flags = offsetof(struct io_rings, cq_flags);3662	p->cq_off.resv1 = 0;3663	if (!(ctx->flags & IORING_SETUP_NO_MMAP))3664		p->cq_off.user_addr = 0;3665 3666	p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |3667			IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |3668			IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |3669			IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED |3670			IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS |3671			IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP |3672			IORING_FEAT_LINKED_FILE | IORING_FEAT_REG_REG_RING |3673			IORING_FEAT_RECVSEND_BUNDLE | IORING_FEAT_MIN_TIMEOUT;3674 3675	if (copy_to_user(params, p, sizeof(*p))) {3676		ret = -EFAULT;3677		goto err;3678	}3679 3680	if (ctx->flags & IORING_SETUP_SINGLE_ISSUER3681	    && !(ctx->flags & IORING_SETUP_R_DISABLED))3682		WRITE_ONCE(ctx->submitter_task, get_task_struct(current));3683 3684	file = io_uring_get_file(ctx);3685	if (IS_ERR(file)) {3686		ret = PTR_ERR(file);3687		goto err;3688	}3689 3690	ret = __io_uring_add_tctx_node(ctx);3691	if (ret)3692		goto err_fput;3693	tctx = current->io_uring;3694 3695	/*3696	 * Install ring fd as the very last thing, so we don't risk someone3697	 * having closed it before we finish setup3698	 */3699	if (p->flags & IORING_SETUP_REGISTERED_FD_ONLY)3700		ret = io_ring_add_registered_file(tctx, file, 0, IO_RINGFD_REG_MAX);3701	else3702		ret = io_uring_install_fd(file);3703	if (ret < 0)3704		goto err_fput;3705 3706	trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);3707	return ret;3708err:3709	io_ring_ctx_wait_and_kill(ctx);3710	return ret;3711err_fput:3712	fput(file);3713	return ret;3714}3715 3716/*3717 * Sets up an aio uring context, and returns the fd. Applications asks for a3718 * ring size, we return the actual sq/cq ring sizes (among other things) in the3719 * params structure passed in.3720 */3721static HWJS_SUSPENDS long io_uring_setup(u32 entries, struct io_uring_params __user *params)3722{3723	struct io_uring_params p;3724	int i;3725 3726	if (copy_from_user(&p, params, sizeof(p)))3727		return -EFAULT;3728	for (i = 0; i < ARRAY_SIZE(p.resv); i++) {3729		if (p.resv[i])3730			return -EINVAL;3731	}3732 3733	if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |3734			IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |3735			IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |3736			IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL |3737			IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG |3738			IORING_SETUP_SQE128 | IORING_SETUP_CQE32 |3739			IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN |3740			IORING_SETUP_NO_MMAP | IORING_SETUP_REGISTERED_FD_ONLY |3741			IORING_SETUP_NO_SQARRAY))3742		return -EINVAL;3743 3744	return io_uring_create(entries, &p, params);3745}3746 3747static inline bool io_uring_allowed(void)3748{3749	int disabled = READ_ONCE(sysctl_io_uring_disabled);3750	kgid_t io_uring_group;3751 3752	if (disabled == 2)3753		return false;3754 3755	if (disabled == 0 || capable(CAP_SYS_ADMIN))3756		return true;3757 3758	io_uring_group = make_kgid(&init_user_ns, sysctl_io_uring_group);3759	if (!gid_valid(io_uring_group))3760		return false;3761 3762	return in_group_p(io_uring_group);3763}3764 3765SYSCALL_DEFINE2(io_uring_setup, u32, entries,3766		struct io_uring_params __user *, params)3767{3768	if (!io_uring_allowed())3769		return -EPERM;3770 3771	return io_uring_setup(entries, params);3772}3773 3774static HWJS_SUSPENDS int __init io_uring_init(void)3775{3776	struct kmem_cache_args kmem_args = {3777		.useroffset = offsetof(struct io_kiocb, cmd.data),3778		.usersize = sizeof_field(struct io_kiocb, cmd.data),3779	};3780 3781#define __BUILD_BUG_VERIFY_OFFSET_SIZE(stype, eoffset, esize, ename) do { \3782	BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \3783	BUILD_BUG_ON(sizeof_field(stype, ename) != esize); \3784} while (0)3785 3786#define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \3787	__BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, sizeof(etype), ename)3788#define BUILD_BUG_SQE_ELEM_SIZE(eoffset, esize, ename) \3789	__BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, esize, ename)3790	BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);3791	BUILD_BUG_SQE_ELEM(0,  __u8,   opcode);3792	BUILD_BUG_SQE_ELEM(1,  __u8,   flags);3793	BUILD_BUG_SQE_ELEM(2,  __u16,  ioprio);3794	BUILD_BUG_SQE_ELEM(4,  __s32,  fd);3795	BUILD_BUG_SQE_ELEM(8,  __u64,  off);3796	BUILD_BUG_SQE_ELEM(8,  __u64,  addr2);3797	BUILD_BUG_SQE_ELEM(8,  __u32,  cmd_op);3798	BUILD_BUG_SQE_ELEM(12, __u32, __pad1);3799	BUILD_BUG_SQE_ELEM(16, __u64,  addr);3800	BUILD_BUG_SQE_ELEM(16, __u64,  splice_off_in);3801	BUILD_BUG_SQE_ELEM(24, __u32,  len);3802	BUILD_BUG_SQE_ELEM(28,     __kernel_rwf_t, rw_flags);3803	BUILD_BUG_SQE_ELEM(28, /* compat */   int, rw_flags);3804	BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);3805	BUILD_BUG_SQE_ELEM(28, __u32,  fsync_flags);3806	BUILD_BUG_SQE_ELEM(28, /* compat */ __u16,  poll_events);3807	BUILD_BUG_SQE_ELEM(28, __u32,  poll32_events);3808	BUILD_BUG_SQE_ELEM(28, __u32,  sync_range_flags);3809	BUILD_BUG_SQE_ELEM(28, __u32,  msg_flags);3810	BUILD_BUG_SQE_ELEM(28, __u32,  timeout_flags);3811	BUILD_BUG_SQE_ELEM(28, __u32,  accept_flags);3812	BUILD_BUG_SQE_ELEM(28, __u32,  cancel_flags);3813	BUILD_BUG_SQE_ELEM(28, __u32,  open_flags);3814	BUILD_BUG_SQE_ELEM(28, __u32,  statx_flags);3815	BUILD_BUG_SQE_ELEM(28, __u32,  fadvise_advice);3816	BUILD_BUG_SQE_ELEM(28, __u32,  splice_flags);3817	BUILD_BUG_SQE_ELEM(28, __u32,  rename_flags);3818	BUILD_BUG_SQE_ELEM(28, __u32,  unlink_flags);3819	BUILD_BUG_SQE_ELEM(28, __u32,  hardlink_flags);3820	BUILD_BUG_SQE_ELEM(28, __u32,  xattr_flags);3821	BUILD_BUG_SQE_ELEM(28, __u32,  msg_ring_flags);3822	BUILD_BUG_SQE_ELEM(32, __u64,  user_data);3823	BUILD_BUG_SQE_ELEM(40, __u16,  buf_index);3824	BUILD_BUG_SQE_ELEM(40, __u16,  buf_group);3825	BUILD_BUG_SQE_ELEM(42, __u16,  personality);3826	BUILD_BUG_SQE_ELEM(44, __s32,  splice_fd_in);3827	BUILD_BUG_SQE_ELEM(44, __u32,  file_index);3828	BUILD_BUG_SQE_ELEM(44, __u16,  addr_len);3829	BUILD_BUG_SQE_ELEM(46, __u16,  __pad3[0]);3830	BUILD_BUG_SQE_ELEM(48, __u64,  addr3);3831	BUILD_BUG_SQE_ELEM_SIZE(48, 0, cmd);3832	BUILD_BUG_SQE_ELEM(56, __u64,  __pad2);3833 3834	BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=3835		     sizeof(struct io_uring_rsrc_update));3836	BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >3837		     sizeof(struct io_uring_rsrc_update2));3838 3839	/* ->buf_index is u16 */3840	BUILD_BUG_ON(offsetof(struct io_uring_buf_ring, bufs) != 0);3841	BUILD_BUG_ON(offsetof(struct io_uring_buf, resv) !=3842		     offsetof(struct io_uring_buf_ring, tail));3843 3844	/* should fit into one byte */3845	BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));3846	BUILD_BUG_ON(SQE_COMMON_FLAGS >= (1 << 8));3847	BUILD_BUG_ON((SQE_VALID_FLAGS | SQE_COMMON_FLAGS) != SQE_VALID_FLAGS);3848 3849	BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof_field(struct io_kiocb, flags));3850 3851	BUILD_BUG_ON(sizeof(atomic_t) != sizeof(u32));3852 3853	/* top 8bits are for internal use */3854	BUILD_BUG_ON((IORING_URING_CMD_MASK & 0xff000000) != 0);3855 3856	io_uring_optable_init();3857 3858	/*3859	 * Allow user copy in the per-command field, which starts after the3860	 * file in io_kiocb and until the opcode field. The openat2 handling3861	 * requires copying in user memory into the io_kiocb object in that3862	 * range, and HARDENED_USERCOPY will complain if we haven't3863	 * correctly annotated this range.3864	 */3865	req_cachep = kmem_cache_create("io_kiocb", sizeof(struct io_kiocb), &kmem_args,3866				SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT |3867				SLAB_TYPESAFE_BY_RCU);3868	io_buf_cachep = KMEM_CACHE(io_buffer,3869					  SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT);3870 3871	iou_wq = alloc_workqueue("iou_exit", WQ_UNBOUND, 64);3872 3873#ifdef CONFIG_SYSCTL3874	register_sysctl_init("kernel", kernel_io_uring_disabled_table);3875#endif3876 3877	return 0;3878};3879__initcall(io_uring_init);3880