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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2003 Sistina Software4 * Copyright (C) 2006 Red Hat GmbH5 *6 * This file is released under the GPL.7 */8 9#include "dm-core.h"10 11#include <linux/device-mapper.h>12 13#include <linux/bio.h>14#include <linux/completion.h>15#include <linux/mempool.h>16#include <linux/module.h>17#include <linux/sched.h>18#include <linux/slab.h>19#include <linux/dm-io.h>20 21#define DM_MSG_PREFIX "io"22 23#define DM_IO_MAX_REGIONS BITS_PER_LONG24 25struct dm_io_client {26 mempool_t pool;27 struct bio_set bios;28};29 30/*31 * Aligning 'struct io' reduces the number of bits required to store32 * its address. Refer to store_io_and_region_in_bio() below.33 */34struct io {35 unsigned long error_bits;36 atomic_t count;37 struct dm_io_client *client;38 io_notify_fn callback;39 void *context;40 void *vma_invalidate_address;41 unsigned long vma_invalidate_size;42} __aligned(DM_IO_MAX_REGIONS);43 44static struct kmem_cache *_dm_io_cache;45 46/*47 * Create a client with mempool and bioset.48 */49struct dm_io_client *dm_io_client_create(void)50{51 struct dm_io_client *client;52 unsigned int min_ios = dm_get_reserved_bio_based_ios();53 int ret;54 55 client = kzalloc(sizeof(*client), GFP_KERNEL);56 if (!client)57 return ERR_PTR(-ENOMEM);58 59 ret = mempool_init_slab_pool(&client->pool, min_ios, _dm_io_cache);60 if (ret)61 goto bad;62 63 ret = bioset_init(&client->bios, min_ios, 0, BIOSET_NEED_BVECS);64 if (ret)65 goto bad;66 67 return client;68 69bad:70 mempool_exit(&client->pool);71 kfree(client);72 return ERR_PTR(ret);73}74EXPORT_SYMBOL(dm_io_client_create);75 76void dm_io_client_destroy(struct dm_io_client *client)77{78 mempool_exit(&client->pool);79 bioset_exit(&client->bios);80 kfree(client);81}82EXPORT_SYMBOL(dm_io_client_destroy);83 84/*85 *-------------------------------------------------------------------86 * We need to keep track of which region a bio is doing io for.87 * To avoid a memory allocation to store just 5 or 6 bits, we88 * ensure the 'struct io' pointer is aligned so enough low bits are89 * always zero and then combine it with the region number directly in90 * bi_private.91 *-------------------------------------------------------------------92 */93static void store_io_and_region_in_bio(struct bio *bio, struct io *io,94 unsigned int region)95{96 if (unlikely(!IS_ALIGNED((unsigned long)io, DM_IO_MAX_REGIONS))) {97 DMCRIT("Unaligned struct io pointer %p", io);98 BUG();99 }100 101 bio->bi_private = (void *)((unsigned long)io | region);102}103 104static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io,105 unsigned int *region)106{107 unsigned long val = (unsigned long)bio->bi_private;108 109 *io = (void *)(val & -(unsigned long)DM_IO_MAX_REGIONS);110 *region = val & (DM_IO_MAX_REGIONS - 1);111}112 113/*114 *--------------------------------------------------------------115 * We need an io object to keep track of the number of bios that116 * have been dispatched for a particular io.117 *--------------------------------------------------------------118 */119static void complete_io(struct io *io)120{121 unsigned long error_bits = io->error_bits;122 io_notify_fn fn = io->callback;123 void *context = io->context;124 125 if (io->vma_invalidate_size)126 invalidate_kernel_vmap_range(io->vma_invalidate_address,127 io->vma_invalidate_size);128 129 mempool_free(io, &io->client->pool);130 fn(error_bits, context);131}132 133static void dec_count(struct io *io, unsigned int region, blk_status_t error)134{135 if (error)136 set_bit(region, &io->error_bits);137 138 if (atomic_dec_and_test(&io->count))139 complete_io(io);140}141 142static void endio(struct bio *bio)143{144 struct io *io;145 unsigned int region;146 blk_status_t error;147 148 if (bio->bi_status && bio_data_dir(bio) == READ)149 zero_fill_bio(bio);150 151 /*152 * The bio destructor in bio_put() may use the io object.153 */154 retrieve_io_and_region_from_bio(bio, &io, ®ion);155 156 error = bio->bi_status;157 bio_put(bio);158 159 dec_count(io, region, error);160}161 162/*163 *--------------------------------------------------------------164 * These little objects provide an abstraction for getting a new165 * destination page for io.166 *--------------------------------------------------------------167 */168struct dpages {169 void (*get_page)(struct dpages *dp,170 struct page **p, unsigned long *len, unsigned int *offset);171 void (*next_page)(struct dpages *dp);172 173 union {174 unsigned int context_u;175 struct bvec_iter context_bi;176 };177 void *context_ptr;178 179 void *vma_invalidate_address;180 unsigned long vma_invalidate_size;181};182 183/*184 * Functions for getting the pages from a list.185 */186static void list_get_page(struct dpages *dp,187 struct page **p, unsigned long *len, unsigned int *offset)188{189 unsigned int o = dp->context_u;190 struct page_list *pl = dp->context_ptr;191 192 *p = pl->page;193 *len = PAGE_SIZE - o;194 *offset = o;195}196 197static void list_next_page(struct dpages *dp)198{199 struct page_list *pl = dp->context_ptr;200 201 dp->context_ptr = pl->next;202 dp->context_u = 0;203}204 205static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned int offset)206{207 dp->get_page = list_get_page;208 dp->next_page = list_next_page;209 dp->context_u = offset;210 dp->context_ptr = pl;211}212 213/*214 * Functions for getting the pages from a bvec.215 */216static void bio_get_page(struct dpages *dp, struct page **p,217 unsigned long *len, unsigned int *offset)218{219 struct bio_vec bvec = bvec_iter_bvec((struct bio_vec *)dp->context_ptr,220 dp->context_bi);221 222 *p = bvec.bv_page;223 *len = bvec.bv_len;224 *offset = bvec.bv_offset;225 226 /* avoid figuring it out again in bio_next_page() */227 dp->context_bi.bi_sector = (sector_t)bvec.bv_len;228}229 230static void bio_next_page(struct dpages *dp)231{232 unsigned int len = (unsigned int)dp->context_bi.bi_sector;233 234 bvec_iter_advance((struct bio_vec *)dp->context_ptr,235 &dp->context_bi, len);236}237 238static void bio_dp_init(struct dpages *dp, struct bio *bio)239{240 dp->get_page = bio_get_page;241 dp->next_page = bio_next_page;242 243 /*244 * We just use bvec iterator to retrieve pages, so it is ok to245 * access the bvec table directly here246 */247 dp->context_ptr = bio->bi_io_vec;248 dp->context_bi = bio->bi_iter;249}250 251/*252 * Functions for getting the pages from a VMA.253 */254static void vm_get_page(struct dpages *dp,255 struct page **p, unsigned long *len, unsigned int *offset)256{257 *p = vmalloc_to_page(dp->context_ptr);258 *offset = dp->context_u;259 *len = PAGE_SIZE - dp->context_u;260}261 262static void vm_next_page(struct dpages *dp)263{264 dp->context_ptr += PAGE_SIZE - dp->context_u;265 dp->context_u = 0;266}267 268static void vm_dp_init(struct dpages *dp, void *data)269{270 dp->get_page = vm_get_page;271 dp->next_page = vm_next_page;272 dp->context_u = offset_in_page(data);273 dp->context_ptr = data;274}275 276/*277 * Functions for getting the pages from kernel memory.278 */279static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,280 unsigned int *offset)281{282 *p = virt_to_page(dp->context_ptr);283 *offset = dp->context_u;284 *len = PAGE_SIZE - dp->context_u;285}286 287static void km_next_page(struct dpages *dp)288{289 dp->context_ptr += PAGE_SIZE - dp->context_u;290 dp->context_u = 0;291}292 293static void km_dp_init(struct dpages *dp, void *data)294{295 dp->get_page = km_get_page;296 dp->next_page = km_next_page;297 dp->context_u = offset_in_page(data);298 dp->context_ptr = data;299}300 301/*302 *---------------------------------------------------------------303 * IO routines that accept a list of pages.304 *---------------------------------------------------------------305 */306static void do_region(const blk_opf_t opf, unsigned int region,307 struct dm_io_region *where, struct dpages *dp,308 struct io *io, unsigned short ioprio)309{310 struct bio *bio;311 struct page *page;312 unsigned long len;313 unsigned int offset;314 unsigned int num_bvecs;315 sector_t remaining = where->count;316 struct request_queue *q = bdev_get_queue(where->bdev);317 sector_t num_sectors;318 unsigned int special_cmd_max_sectors;319 const enum req_op op = opf & REQ_OP_MASK;320 321 /*322 * Reject unsupported discard and write same requests.323 */324 if (op == REQ_OP_DISCARD)325 special_cmd_max_sectors = bdev_max_discard_sectors(where->bdev);326 else if (op == REQ_OP_WRITE_ZEROES)327 special_cmd_max_sectors = q->limits.max_write_zeroes_sectors;328 if ((op == REQ_OP_DISCARD || op == REQ_OP_WRITE_ZEROES) &&329 special_cmd_max_sectors == 0) {330 atomic_inc(&io->count);331 dec_count(io, region, BLK_STS_NOTSUPP);332 return;333 }334 335 /*336 * where->count may be zero if op holds a flush and we need to337 * send a zero-sized flush.338 */339 do {340 /*341 * Allocate a suitably sized-bio.342 */343 switch (op) {344 case REQ_OP_DISCARD:345 case REQ_OP_WRITE_ZEROES:346 num_bvecs = 0;347 break;348 default:349 num_bvecs = bio_max_segs(dm_sector_div_up(remaining,350 (PAGE_SIZE >> SECTOR_SHIFT)) + 1);351 }352 353 bio = bio_alloc_bioset(where->bdev, num_bvecs, opf, GFP_NOIO,354 &io->client->bios);355 bio->bi_iter.bi_sector = where->sector + (where->count - remaining);356 bio->bi_end_io = endio;357 bio->bi_ioprio = ioprio;358 store_io_and_region_in_bio(bio, io, region);359 360 if (op == REQ_OP_DISCARD || op == REQ_OP_WRITE_ZEROES) {361 num_sectors = min_t(sector_t, special_cmd_max_sectors, remaining);362 bio->bi_iter.bi_size = num_sectors << SECTOR_SHIFT;363 remaining -= num_sectors;364 } else {365 while (remaining) {366 /*367 * Try and add as many pages as possible.368 */369 dp->get_page(dp, &page, &len, &offset);370 len = min(len, to_bytes(remaining));371 if (!bio_add_page(bio, page, len, offset))372 break;373 374 offset = 0;375 remaining -= to_sector(len);376 dp->next_page(dp);377 }378 }379 380 atomic_inc(&io->count);381 submit_bio(bio);382 } while (remaining);383}384 385static void dispatch_io(blk_opf_t opf, unsigned int num_regions,386 struct dm_io_region *where, struct dpages *dp,387 struct io *io, unsigned short ioprio)388{389 int i;390 struct dpages old_pages = *dp;391 392 BUG_ON(num_regions > DM_IO_MAX_REGIONS);393 394 /*395 * For multiple regions we need to be careful to rewind396 * the dp object for each call to do_region.397 */398 for (i = 0; i < num_regions; i++) {399 *dp = old_pages;400 if (where[i].count || (opf & REQ_PREFLUSH))401 do_region(opf, i, where + i, dp, io, ioprio);402 }403 404 /*405 * Drop the extra reference that we were holding to avoid406 * the io being completed too early.407 */408 dec_count(io, 0, 0);409}410 411static void async_io(struct dm_io_client *client, unsigned int num_regions,412 struct dm_io_region *where, blk_opf_t opf,413 struct dpages *dp, io_notify_fn fn, void *context,414 unsigned short ioprio)415{416 struct io *io;417 418 io = mempool_alloc(&client->pool, GFP_NOIO);419 io->error_bits = 0;420 atomic_set(&io->count, 1); /* see dispatch_io() */421 io->client = client;422 io->callback = fn;423 io->context = context;424 425 io->vma_invalidate_address = dp->vma_invalidate_address;426 io->vma_invalidate_size = dp->vma_invalidate_size;427 428 dispatch_io(opf, num_regions, where, dp, io, ioprio);429}430 431struct sync_io {432 unsigned long error_bits;433 struct completion wait;434};435 436static void sync_io_complete(unsigned long error, void *context)437{438 struct sync_io *sio = context;439 440 sio->error_bits = error;441 complete(&sio->wait);442}443 444static int sync_io(struct dm_io_client *client, unsigned int num_regions,445 struct dm_io_region *where, blk_opf_t opf, struct dpages *dp,446 unsigned long *error_bits, unsigned short ioprio)447{448 struct sync_io sio;449 450 init_completion(&sio.wait);451 452 async_io(client, num_regions, where, opf | REQ_SYNC, dp,453 sync_io_complete, &sio, ioprio);454 455 wait_for_completion_io(&sio.wait);456 457 if (error_bits)458 *error_bits = sio.error_bits;459 460 return sio.error_bits ? -EIO : 0;461}462 463static int dp_init(struct dm_io_request *io_req, struct dpages *dp,464 unsigned long size)465{466 /* Set up dpages based on memory type */467 468 dp->vma_invalidate_address = NULL;469 dp->vma_invalidate_size = 0;470 471 switch (io_req->mem.type) {472 case DM_IO_PAGE_LIST:473 list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);474 break;475 476 case DM_IO_BIO:477 bio_dp_init(dp, io_req->mem.ptr.bio);478 break;479 480 case DM_IO_VMA:481 flush_kernel_vmap_range(io_req->mem.ptr.vma, size);482 if ((io_req->bi_opf & REQ_OP_MASK) == REQ_OP_READ) {483 dp->vma_invalidate_address = io_req->mem.ptr.vma;484 dp->vma_invalidate_size = size;485 }486 vm_dp_init(dp, io_req->mem.ptr.vma);487 break;488 489 case DM_IO_KMEM:490 km_dp_init(dp, io_req->mem.ptr.addr);491 break;492 493 default:494 return -EINVAL;495 }496 497 return 0;498}499 500int dm_io(struct dm_io_request *io_req, unsigned int num_regions,501 struct dm_io_region *where, unsigned long *sync_error_bits,502 unsigned short ioprio)503{504 int r;505 struct dpages dp;506 507 if (num_regions > 1 && !op_is_write(io_req->bi_opf)) {508 WARN_ON(1);509 return -EIO;510 }511 512 r = dp_init(io_req, &dp, (unsigned long)where->count << SECTOR_SHIFT);513 if (r)514 return r;515 516 if (!io_req->notify.fn)517 return sync_io(io_req->client, num_regions, where,518 io_req->bi_opf, &dp, sync_error_bits, ioprio);519 520 async_io(io_req->client, num_regions, where, io_req->bi_opf, &dp,521 io_req->notify.fn, io_req->notify.context, ioprio);522 return 0;523}524EXPORT_SYMBOL(dm_io);525 526int __init dm_io_init(void)527{528 _dm_io_cache = KMEM_CACHE(io, 0);529 if (!_dm_io_cache)530 return -ENOMEM;531 532 return 0;533}534 535void dm_io_exit(void)536{537 kmem_cache_destroy(_dm_io_cache);538 _dm_io_cache = NULL;539}540