1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * BSG helper library 4 * 5 * Copyright (C) 2008 James Smart, Emulex Corporation 6 * Copyright (C) 2011 Red Hat, Inc. All rights reserved. 7 * Copyright (C) 2011 Mike Christie 8 */ 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 21 struct 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 28 static int bsg_transport_sg_io_fn(struct request_queue *q, struct sg_io_v4 *hdr, 29 fmode_t mode, 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 for 99 * 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 else 121 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 else 133 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); 139 out_unmap_bidi_rq: 140 if (job->bidi_rq) 141 blk_rq_unmap_user(job->bidi_bio); 142 out_free_bidi_rq: 143 if (job->bidi_rq) 144 blk_mq_free_request(job->bidi_rq); 145 out_free_job_request: 146 kfree(job->request); 147 out_free_rq: 148 blk_mq_free_request(rq); 149 return ret; 150 } 151 152 /** 153 * bsg_teardown_job - routine to teardown a bsg job 154 * @kref: kref inside bsg_job that is to be torn down 155 */ 156 static 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 } 168 169 void bsg_job_put(struct bsg_job *job) 170 { 171 kref_put(&job->kref, bsg_teardown_job); 172 } 173 EXPORT_SYMBOL_GPL(bsg_job_put); 174 175 int bsg_job_get(struct bsg_job *job) 176 { 177 return kref_get_unless_zero(&job->kref); 178 } 179 EXPORT_SYMBOL_GPL(bsg_job_get); 180 181 /** 182 * bsg_job_done - completion routine for bsg requests 183 * @job: bsg_job that is complete 184 * @result: job reply result 185 * @reply_payload_rcv_len: length of payload recvd 186 * 187 * The LLD should call this when the bsg job has completed. 188 */ 189 void 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 } 199 EXPORT_SYMBOL_GPL(bsg_job_done); 200 201 /** 202 * bsg_complete - softirq done routine for destroying the bsg requests 203 * @rq: BSG request that holds the job to be destroyed 204 */ 205 static 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 } 211 212 static 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 request 229 * @dev: device that is being sent the bsg request 230 * @req: BSG request that needs a job structure 231 */ 232 static 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; 254 255 failjob_rls_rqst_payload: 256 kfree(job->request_payload.sg_list); 257 failjob_rls_job: 258 job->result = -ENOMEM; 259 return false; 260 } 261 262 /** 263 * bsg_queue_rq - generic handler for bsg requests 264 * @hctx: hardware queue 265 * @bd: queue data 266 * 267 * On error the create_bsg_job function should return a -Exyz error value 268 * that will be set to ->result. 269 * 270 * Drivers/subsys should pass this to the queue init function. 271 */ 272 static 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; 294 295 out: 296 put_device(dev); 297 return sts; 298 } 299 300 /* called right after the request is allocated for the request_queue */ 301 static 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 } 311 312 static 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 } 319 320 void 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_cleanup_queue(q); 328 blk_mq_free_tag_set(&bset->tag_set); 329 kfree(bset); 330 } 331 } 332 EXPORT_SYMBOL_GPL(bsg_remove_queue); 333 334 static enum blk_eh_timer_return bsg_timeout(struct request *rq, bool reserved) 335 { 336 struct bsg_set *bset = 337 container_of(rq->q->tag_set, struct bsg_set, tag_set); 338 339 if (!bset->timeout_fn) 340 return BLK_EH_DONE; 341 return bset->timeout_fn(rq); 342 } 343 344 static const struct blk_mq_ops bsg_mq_ops = { 345 .queue_rq = bsg_queue_rq, 346 .init_request = bsg_init_rq, 347 .exit_request = bsg_exit_rq, 348 .complete = bsg_complete, 349 .timeout = bsg_timeout, 350 }; 351 352 /** 353 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests 354 * @dev: device to attach bsg device to 355 * @name: device to give bsg device 356 * @job_fn: bsg job handler 357 * @timeout: timeout handler function pointer 358 * @dd_job_size: size of LLD data needed for each job 359 */ 360 struct request_queue *bsg_setup_queue(struct device *dev, const char *name, 361 bsg_job_fn *job_fn, bsg_timeout_fn *timeout, int dd_job_size) 362 { 363 struct bsg_set *bset; 364 struct blk_mq_tag_set *set; 365 struct request_queue *q; 366 int ret = -ENOMEM; 367 368 bset = kzalloc(sizeof(*bset), GFP_KERNEL); 369 if (!bset) 370 return ERR_PTR(-ENOMEM); 371 372 bset->job_fn = job_fn; 373 bset->timeout_fn = timeout; 374 375 set = &bset->tag_set; 376 set->ops = &bsg_mq_ops; 377 set->nr_hw_queues = 1; 378 set->queue_depth = 128; 379 set->numa_node = NUMA_NO_NODE; 380 set->cmd_size = sizeof(struct bsg_job) + dd_job_size; 381 set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING; 382 if (blk_mq_alloc_tag_set(set)) 383 goto out_tag_set; 384 385 q = blk_mq_init_queue(set); 386 if (IS_ERR(q)) { 387 ret = PTR_ERR(q); 388 goto out_queue; 389 } 390 391 q->queuedata = dev; 392 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); 393 394 bset->bd = bsg_register_queue(q, dev, name, bsg_transport_sg_io_fn); 395 if (IS_ERR(bset->bd)) { 396 ret = PTR_ERR(bset->bd); 397 goto out_cleanup_queue; 398 } 399 400 return q; 401 out_cleanup_queue: 402 blk_cleanup_queue(q); 403 out_queue: 404 blk_mq_free_tag_set(set); 405 out_tag_set: 406 kfree(bset); 407 return ERR_PTR(ret); 408 } 409 EXPORT_SYMBOL_GPL(bsg_setup_queue); 410