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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * BSG helper library4 *5 * Copyright (C) 2008 James Smart, Emulex Corporation6 * Copyright (C) 2011 Red Hat, Inc. All rights reserved.7 * Copyright (C) 2011 Mike Christie8 */9#include <linux/bsg.h>10#include <linux/slab.h>11#include <linux/blk-mq.h>12#include <linux/delay.h>13#include <linux/scatterlist.h>14#include <linux/bsg-lib.h>15#include <linux/export.h>16#include <scsi/scsi_cmnd.h>17#include <scsi/sg.h>18 19#define uptr64(val) ((void __user *)(uintptr_t)(val))20 21struct bsg_set {22 struct blk_mq_tag_set tag_set;23 struct bsg_device *bd;24 bsg_job_fn *job_fn;25 bsg_timeout_fn *timeout_fn;26};27 28static int bsg_transport_sg_io_fn(struct request_queue *q, struct sg_io_v4 *hdr,29 bool open_for_write, unsigned int timeout)30{31 struct bsg_job *job;32 struct request *rq;33 struct bio *bio;34 void *reply;35 int ret;36 37 if (hdr->protocol != BSG_PROTOCOL_SCSI ||38 hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_TRANSPORT)39 return -EINVAL;40 if (!capable(CAP_SYS_RAWIO))41 return -EPERM;42 43 rq = blk_mq_alloc_request(q, hdr->dout_xfer_len ?44 REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);45 if (IS_ERR(rq))46 return PTR_ERR(rq);47 rq->timeout = timeout;48 49 job = blk_mq_rq_to_pdu(rq);50 reply = job->reply;51 memset(job, 0, sizeof(*job));52 job->reply = reply;53 job->reply_len = SCSI_SENSE_BUFFERSIZE;54 job->dd_data = job + 1;55 56 job->request_len = hdr->request_len;57 job->request = memdup_user(uptr64(hdr->request), hdr->request_len);58 if (IS_ERR(job->request)) {59 ret = PTR_ERR(job->request);60 goto out_free_rq;61 }62 63 if (hdr->dout_xfer_len && hdr->din_xfer_len) {64 job->bidi_rq = blk_mq_alloc_request(rq->q, REQ_OP_DRV_IN, 0);65 if (IS_ERR(job->bidi_rq)) {66 ret = PTR_ERR(job->bidi_rq);67 goto out_free_job_request;68 }69 70 ret = blk_rq_map_user(rq->q, job->bidi_rq, NULL,71 uptr64(hdr->din_xferp), hdr->din_xfer_len,72 GFP_KERNEL);73 if (ret)74 goto out_free_bidi_rq;75 76 job->bidi_bio = job->bidi_rq->bio;77 } else {78 job->bidi_rq = NULL;79 job->bidi_bio = NULL;80 }81 82 ret = 0;83 if (hdr->dout_xfer_len) {84 ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->dout_xferp),85 hdr->dout_xfer_len, GFP_KERNEL);86 } else if (hdr->din_xfer_len) {87 ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->din_xferp),88 hdr->din_xfer_len, GFP_KERNEL);89 }90 91 if (ret)92 goto out_unmap_bidi_rq;93 94 bio = rq->bio;95 blk_execute_rq(rq, !(hdr->flags & BSG_FLAG_Q_AT_TAIL));96 97 /*98 * The assignments below don't make much sense, but are kept for99 * bug by bug backwards compatibility:100 */101 hdr->device_status = job->result & 0xff;102 hdr->transport_status = host_byte(job->result);103 hdr->driver_status = 0;104 hdr->info = 0;105 if (hdr->device_status || hdr->transport_status || hdr->driver_status)106 hdr->info |= SG_INFO_CHECK;107 hdr->response_len = 0;108 109 if (job->result < 0) {110 /* we're only returning the result field in the reply */111 job->reply_len = sizeof(u32);112 ret = job->result;113 }114 115 if (job->reply_len && hdr->response) {116 int len = min(hdr->max_response_len, job->reply_len);117 118 if (copy_to_user(uptr64(hdr->response), job->reply, len))119 ret = -EFAULT;120 else121 hdr->response_len = len;122 }123 124 /* we assume all request payload was transferred, residual == 0 */125 hdr->dout_resid = 0;126 127 if (job->bidi_rq) {128 unsigned int rsp_len = job->reply_payload.payload_len;129 130 if (WARN_ON(job->reply_payload_rcv_len > rsp_len))131 hdr->din_resid = 0;132 else133 hdr->din_resid = rsp_len - job->reply_payload_rcv_len;134 } else {135 hdr->din_resid = 0;136 }137 138 blk_rq_unmap_user(bio);139out_unmap_bidi_rq:140 if (job->bidi_rq)141 blk_rq_unmap_user(job->bidi_bio);142out_free_bidi_rq:143 if (job->bidi_rq)144 blk_mq_free_request(job->bidi_rq);145out_free_job_request:146 kfree(job->request);147out_free_rq:148 blk_mq_free_request(rq);149 return ret;150}151 152/**153 * bsg_teardown_job - routine to teardown a bsg job154 * @kref: kref inside bsg_job that is to be torn down155 */156static void bsg_teardown_job(struct kref *kref)157{158 struct bsg_job *job = container_of(kref, struct bsg_job, kref);159 struct request *rq = blk_mq_rq_from_pdu(job);160 161 put_device(job->dev); /* release reference for the request */162 163 kfree(job->request_payload.sg_list);164 kfree(job->reply_payload.sg_list);165 166 blk_mq_end_request(rq, BLK_STS_OK);167}168 169void bsg_job_put(struct bsg_job *job)170{171 kref_put(&job->kref, bsg_teardown_job);172}173EXPORT_SYMBOL_GPL(bsg_job_put);174 175int bsg_job_get(struct bsg_job *job)176{177 return kref_get_unless_zero(&job->kref);178}179EXPORT_SYMBOL_GPL(bsg_job_get);180 181/**182 * bsg_job_done - completion routine for bsg requests183 * @job: bsg_job that is complete184 * @result: job reply result185 * @reply_payload_rcv_len: length of payload recvd186 *187 * The LLD should call this when the bsg job has completed.188 */189void bsg_job_done(struct bsg_job *job, int result,190 unsigned int reply_payload_rcv_len)191{192 struct request *rq = blk_mq_rq_from_pdu(job);193 194 job->result = result;195 job->reply_payload_rcv_len = reply_payload_rcv_len;196 if (likely(!blk_should_fake_timeout(rq->q)))197 blk_mq_complete_request(rq);198}199EXPORT_SYMBOL_GPL(bsg_job_done);200 201/**202 * bsg_complete - softirq done routine for destroying the bsg requests203 * @rq: BSG request that holds the job to be destroyed204 */205static void bsg_complete(struct request *rq)206{207 struct bsg_job *job = blk_mq_rq_to_pdu(rq);208 209 bsg_job_put(job);210}211 212static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)213{214 size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);215 216 BUG_ON(!req->nr_phys_segments);217 218 buf->sg_list = kmalloc(sz, GFP_KERNEL);219 if (!buf->sg_list)220 return -ENOMEM;221 sg_init_table(buf->sg_list, req->nr_phys_segments);222 buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);223 buf->payload_len = blk_rq_bytes(req);224 return 0;225}226 227/**228 * bsg_prepare_job - create the bsg_job structure for the bsg request229 * @dev: device that is being sent the bsg request230 * @req: BSG request that needs a job structure231 */232static bool bsg_prepare_job(struct device *dev, struct request *req)233{234 struct bsg_job *job = blk_mq_rq_to_pdu(req);235 int ret;236 237 job->timeout = req->timeout;238 239 if (req->bio) {240 ret = bsg_map_buffer(&job->request_payload, req);241 if (ret)242 goto failjob_rls_job;243 }244 if (job->bidi_rq) {245 ret = bsg_map_buffer(&job->reply_payload, job->bidi_rq);246 if (ret)247 goto failjob_rls_rqst_payload;248 }249 job->dev = dev;250 /* take a reference for the request */251 get_device(job->dev);252 kref_init(&job->kref);253 return true;254 255failjob_rls_rqst_payload:256 kfree(job->request_payload.sg_list);257failjob_rls_job:258 job->result = -ENOMEM;259 return false;260}261 262/**263 * bsg_queue_rq - generic handler for bsg requests264 * @hctx: hardware queue265 * @bd: queue data266 *267 * On error the create_bsg_job function should return a -Exyz error value268 * that will be set to ->result.269 *270 * Drivers/subsys should pass this to the queue init function.271 */272static blk_status_t bsg_queue_rq(struct blk_mq_hw_ctx *hctx,273 const struct blk_mq_queue_data *bd)274{275 struct request_queue *q = hctx->queue;276 struct device *dev = q->queuedata;277 struct request *req = bd->rq;278 struct bsg_set *bset =279 container_of(q->tag_set, struct bsg_set, tag_set);280 blk_status_t sts = BLK_STS_IOERR;281 int ret;282 283 blk_mq_start_request(req);284 285 if (!get_device(dev))286 return BLK_STS_IOERR;287 288 if (!bsg_prepare_job(dev, req))289 goto out;290 291 ret = bset->job_fn(blk_mq_rq_to_pdu(req));292 if (!ret)293 sts = BLK_STS_OK;294 295out:296 put_device(dev);297 return sts;298}299 300/* called right after the request is allocated for the request_queue */301static int bsg_init_rq(struct blk_mq_tag_set *set, struct request *req,302 unsigned int hctx_idx, unsigned int numa_node)303{304 struct bsg_job *job = blk_mq_rq_to_pdu(req);305 306 job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL);307 if (!job->reply)308 return -ENOMEM;309 return 0;310}311 312static void bsg_exit_rq(struct blk_mq_tag_set *set, struct request *req,313 unsigned int hctx_idx)314{315 struct bsg_job *job = blk_mq_rq_to_pdu(req);316 317 kfree(job->reply);318}319 320void bsg_remove_queue(struct request_queue *q)321{322 if (q) {323 struct bsg_set *bset =324 container_of(q->tag_set, struct bsg_set, tag_set);325 326 bsg_unregister_queue(bset->bd);327 blk_mq_destroy_queue(q);328 blk_put_queue(q);329 blk_mq_free_tag_set(&bset->tag_set);330 kfree(bset);331 }332}333EXPORT_SYMBOL_GPL(bsg_remove_queue);334 335static enum blk_eh_timer_return bsg_timeout(struct request *rq)336{337 struct bsg_set *bset =338 container_of(rq->q->tag_set, struct bsg_set, tag_set);339 340 if (!bset->timeout_fn)341 return BLK_EH_DONE;342 return bset->timeout_fn(rq);343}344 345static const struct blk_mq_ops bsg_mq_ops = {346 .queue_rq = bsg_queue_rq,347 .init_request = bsg_init_rq,348 .exit_request = bsg_exit_rq,349 .complete = bsg_complete,350 .timeout = bsg_timeout,351};352 353/**354 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests355 * @dev: device to attach bsg device to356 * @name: device to give bsg device357 * @lim: queue limits for the bsg queue358 * @job_fn: bsg job handler359 * @timeout: timeout handler function pointer360 * @dd_job_size: size of LLD data needed for each job361 */362struct request_queue *bsg_setup_queue(struct device *dev, const char *name,363 struct queue_limits *lim, bsg_job_fn *job_fn,364 bsg_timeout_fn *timeout, int dd_job_size)365{366 struct bsg_set *bset;367 struct blk_mq_tag_set *set;368 struct request_queue *q;369 int ret = -ENOMEM;370 371 bset = kzalloc(sizeof(*bset), GFP_KERNEL);372 if (!bset)373 return ERR_PTR(-ENOMEM);374 375 bset->job_fn = job_fn;376 bset->timeout_fn = timeout;377 378 set = &bset->tag_set;379 set->ops = &bsg_mq_ops;380 set->nr_hw_queues = 1;381 set->queue_depth = 128;382 set->numa_node = NUMA_NO_NODE;383 set->cmd_size = sizeof(struct bsg_job) + dd_job_size;384 set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING;385 if (blk_mq_alloc_tag_set(set))386 goto out_tag_set;387 388 q = blk_mq_alloc_queue(set, lim, dev);389 if (IS_ERR(q)) {390 ret = PTR_ERR(q);391 goto out_queue;392 }393 394 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);395 396 bset->bd = bsg_register_queue(q, dev, name, bsg_transport_sg_io_fn);397 if (IS_ERR(bset->bd)) {398 ret = PTR_ERR(bset->bd);399 goto out_cleanup_queue;400 }401 402 return q;403out_cleanup_queue:404 blk_mq_destroy_queue(q);405 blk_put_queue(q);406out_queue:407 blk_mq_free_tag_set(set);408out_tag_set:409 kfree(bset);410 return ERR_PTR(ret);411}412EXPORT_SYMBOL_GPL(bsg_setup_queue);413