1 /* 2 * BSG helper library 3 * 4 * Copyright (C) 2008 James Smart, Emulex Corporation 5 * Copyright (C) 2011 Red Hat, Inc. All rights reserved. 6 * Copyright (C) 2011 Mike Christie 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21 * 22 */ 23 #include <linux/slab.h> 24 #include <linux/blk-mq.h> 25 #include <linux/delay.h> 26 #include <linux/scatterlist.h> 27 #include <linux/bsg-lib.h> 28 #include <linux/export.h> 29 #include <scsi/scsi_cmnd.h> 30 #include <scsi/sg.h> 31 32 #define uptr64(val) ((void __user *)(uintptr_t)(val)) 33 34 struct bsg_set { 35 struct blk_mq_tag_set tag_set; 36 bsg_job_fn *job_fn; 37 bsg_timeout_fn *timeout_fn; 38 }; 39 40 static int bsg_transport_check_proto(struct sg_io_v4 *hdr) 41 { 42 if (hdr->protocol != BSG_PROTOCOL_SCSI || 43 hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_TRANSPORT) 44 return -EINVAL; 45 if (!capable(CAP_SYS_RAWIO)) 46 return -EPERM; 47 return 0; 48 } 49 50 static int bsg_transport_fill_hdr(struct request *rq, struct sg_io_v4 *hdr, 51 fmode_t mode) 52 { 53 struct bsg_job *job = blk_mq_rq_to_pdu(rq); 54 int ret; 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 return PTR_ERR(job->request); 60 61 if (hdr->dout_xfer_len && hdr->din_xfer_len) { 62 job->bidi_rq = blk_get_request(rq->q, REQ_OP_SCSI_IN, 0); 63 if (IS_ERR(job->bidi_rq)) { 64 ret = PTR_ERR(job->bidi_rq); 65 goto out; 66 } 67 68 ret = blk_rq_map_user(rq->q, job->bidi_rq, NULL, 69 uptr64(hdr->din_xferp), hdr->din_xfer_len, 70 GFP_KERNEL); 71 if (ret) 72 goto out_free_bidi_rq; 73 74 job->bidi_bio = job->bidi_rq->bio; 75 } else { 76 job->bidi_rq = NULL; 77 job->bidi_bio = NULL; 78 } 79 80 return 0; 81 82 out_free_bidi_rq: 83 if (job->bidi_rq) 84 blk_put_request(job->bidi_rq); 85 out: 86 kfree(job->request); 87 return ret; 88 } 89 90 static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr) 91 { 92 struct bsg_job *job = blk_mq_rq_to_pdu(rq); 93 int ret = 0; 94 95 /* 96 * The assignments below don't make much sense, but are kept for 97 * bug by bug backwards compatibility: 98 */ 99 hdr->device_status = job->result & 0xff; 100 hdr->transport_status = host_byte(job->result); 101 hdr->driver_status = driver_byte(job->result); 102 hdr->info = 0; 103 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 104 hdr->info |= SG_INFO_CHECK; 105 hdr->response_len = 0; 106 107 if (job->result < 0) { 108 /* we're only returning the result field in the reply */ 109 job->reply_len = sizeof(u32); 110 ret = job->result; 111 } 112 113 if (job->reply_len && hdr->response) { 114 int len = min(hdr->max_response_len, job->reply_len); 115 116 if (copy_to_user(uptr64(hdr->response), job->reply, len)) 117 ret = -EFAULT; 118 else 119 hdr->response_len = len; 120 } 121 122 /* we assume all request payload was transferred, residual == 0 */ 123 hdr->dout_resid = 0; 124 125 if (job->bidi_rq) { 126 unsigned int rsp_len = job->reply_payload.payload_len; 127 128 if (WARN_ON(job->reply_payload_rcv_len > rsp_len)) 129 hdr->din_resid = 0; 130 else 131 hdr->din_resid = rsp_len - job->reply_payload_rcv_len; 132 } else { 133 hdr->din_resid = 0; 134 } 135 136 return ret; 137 } 138 139 static void bsg_transport_free_rq(struct request *rq) 140 { 141 struct bsg_job *job = blk_mq_rq_to_pdu(rq); 142 143 if (job->bidi_rq) { 144 blk_rq_unmap_user(job->bidi_bio); 145 blk_put_request(job->bidi_rq); 146 } 147 148 kfree(job->request); 149 } 150 151 static const struct bsg_ops bsg_transport_ops = { 152 .check_proto = bsg_transport_check_proto, 153 .fill_hdr = bsg_transport_fill_hdr, 154 .complete_rq = bsg_transport_complete_rq, 155 .free_rq = bsg_transport_free_rq, 156 }; 157 158 /** 159 * bsg_teardown_job - routine to teardown a bsg job 160 * @kref: kref inside bsg_job that is to be torn down 161 */ 162 static void bsg_teardown_job(struct kref *kref) 163 { 164 struct bsg_job *job = container_of(kref, struct bsg_job, kref); 165 struct request *rq = blk_mq_rq_from_pdu(job); 166 167 put_device(job->dev); /* release reference for the request */ 168 169 kfree(job->request_payload.sg_list); 170 kfree(job->reply_payload.sg_list); 171 172 blk_mq_end_request(rq, BLK_STS_OK); 173 } 174 175 void bsg_job_put(struct bsg_job *job) 176 { 177 kref_put(&job->kref, bsg_teardown_job); 178 } 179 EXPORT_SYMBOL_GPL(bsg_job_put); 180 181 int bsg_job_get(struct bsg_job *job) 182 { 183 return kref_get_unless_zero(&job->kref); 184 } 185 EXPORT_SYMBOL_GPL(bsg_job_get); 186 187 /** 188 * bsg_job_done - completion routine for bsg requests 189 * @job: bsg_job that is complete 190 * @result: job reply result 191 * @reply_payload_rcv_len: length of payload recvd 192 * 193 * The LLD should call this when the bsg job has completed. 194 */ 195 void bsg_job_done(struct bsg_job *job, int result, 196 unsigned int reply_payload_rcv_len) 197 { 198 job->result = result; 199 job->reply_payload_rcv_len = reply_payload_rcv_len; 200 blk_mq_complete_request(blk_mq_rq_from_pdu(job)); 201 } 202 EXPORT_SYMBOL_GPL(bsg_job_done); 203 204 /** 205 * bsg_complete - softirq done routine for destroying the bsg requests 206 * @rq: BSG request that holds the job to be destroyed 207 */ 208 static void bsg_complete(struct request *rq) 209 { 210 struct bsg_job *job = blk_mq_rq_to_pdu(rq); 211 212 bsg_job_put(job); 213 } 214 215 static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req) 216 { 217 size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments); 218 219 BUG_ON(!req->nr_phys_segments); 220 221 buf->sg_list = kzalloc(sz, GFP_KERNEL); 222 if (!buf->sg_list) 223 return -ENOMEM; 224 sg_init_table(buf->sg_list, req->nr_phys_segments); 225 buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list); 226 buf->payload_len = blk_rq_bytes(req); 227 return 0; 228 } 229 230 /** 231 * bsg_prepare_job - create the bsg_job structure for the bsg request 232 * @dev: device that is being sent the bsg request 233 * @req: BSG request that needs a job structure 234 */ 235 static bool bsg_prepare_job(struct device *dev, struct request *req) 236 { 237 struct bsg_job *job = blk_mq_rq_to_pdu(req); 238 int ret; 239 240 job->timeout = req->timeout; 241 242 if (req->bio) { 243 ret = bsg_map_buffer(&job->request_payload, req); 244 if (ret) 245 goto failjob_rls_job; 246 } 247 if (job->bidi_rq) { 248 ret = bsg_map_buffer(&job->reply_payload, job->bidi_rq); 249 if (ret) 250 goto failjob_rls_rqst_payload; 251 } 252 job->dev = dev; 253 /* take a reference for the request */ 254 get_device(job->dev); 255 kref_init(&job->kref); 256 return true; 257 258 failjob_rls_rqst_payload: 259 kfree(job->request_payload.sg_list); 260 failjob_rls_job: 261 job->result = -ENOMEM; 262 return false; 263 } 264 265 /** 266 * bsg_queue_rq - generic handler for bsg requests 267 * @hctx: hardware queue 268 * @bd: queue data 269 * 270 * On error the create_bsg_job function should return a -Exyz error value 271 * that will be set to ->result. 272 * 273 * Drivers/subsys should pass this to the queue init function. 274 */ 275 static blk_status_t bsg_queue_rq(struct blk_mq_hw_ctx *hctx, 276 const struct blk_mq_queue_data *bd) 277 { 278 struct request_queue *q = hctx->queue; 279 struct device *dev = q->queuedata; 280 struct request *req = bd->rq; 281 struct bsg_set *bset = 282 container_of(q->tag_set, struct bsg_set, tag_set); 283 int ret; 284 285 blk_mq_start_request(req); 286 287 if (!get_device(dev)) 288 return BLK_STS_IOERR; 289 290 if (!bsg_prepare_job(dev, req)) 291 return BLK_STS_IOERR; 292 293 ret = bset->job_fn(blk_mq_rq_to_pdu(req)); 294 if (ret) 295 return BLK_STS_IOERR; 296 297 put_device(dev); 298 return BLK_STS_OK; 299 } 300 301 /* called right after the request is allocated for the request_queue */ 302 static int bsg_init_rq(struct blk_mq_tag_set *set, struct request *req, 303 unsigned int hctx_idx, unsigned int numa_node) 304 { 305 struct bsg_job *job = blk_mq_rq_to_pdu(req); 306 307 job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL); 308 if (!job->reply) 309 return -ENOMEM; 310 return 0; 311 } 312 313 /* called right before the request is given to the request_queue user */ 314 static void bsg_initialize_rq(struct request *req) 315 { 316 struct bsg_job *job = blk_mq_rq_to_pdu(req); 317 void *reply = job->reply; 318 319 memset(job, 0, sizeof(*job)); 320 job->reply = reply; 321 job->reply_len = SCSI_SENSE_BUFFERSIZE; 322 job->dd_data = job + 1; 323 } 324 325 static void bsg_exit_rq(struct blk_mq_tag_set *set, struct request *req, 326 unsigned int hctx_idx) 327 { 328 struct bsg_job *job = blk_mq_rq_to_pdu(req); 329 330 kfree(job->reply); 331 } 332 333 void bsg_remove_queue(struct request_queue *q) 334 { 335 if (q) { 336 struct bsg_set *bset = 337 container_of(q->tag_set, struct bsg_set, tag_set); 338 339 bsg_unregister_queue(q); 340 blk_cleanup_queue(q); 341 blk_mq_free_tag_set(&bset->tag_set); 342 kfree(bset); 343 } 344 } 345 EXPORT_SYMBOL_GPL(bsg_remove_queue); 346 347 static enum blk_eh_timer_return bsg_timeout(struct request *rq, bool reserved) 348 { 349 struct bsg_set *bset = 350 container_of(rq->q->tag_set, struct bsg_set, tag_set); 351 352 if (!bset->timeout_fn) 353 return BLK_EH_DONE; 354 return bset->timeout_fn(rq); 355 } 356 357 static const struct blk_mq_ops bsg_mq_ops = { 358 .queue_rq = bsg_queue_rq, 359 .init_request = bsg_init_rq, 360 .exit_request = bsg_exit_rq, 361 .initialize_rq_fn = bsg_initialize_rq, 362 .complete = bsg_complete, 363 .timeout = bsg_timeout, 364 }; 365 366 /** 367 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests 368 * @dev: device to attach bsg device to 369 * @name: device to give bsg device 370 * @job_fn: bsg job handler 371 * @dd_job_size: size of LLD data needed for each job 372 */ 373 struct request_queue *bsg_setup_queue(struct device *dev, const char *name, 374 bsg_job_fn *job_fn, bsg_timeout_fn *timeout, int dd_job_size) 375 { 376 struct bsg_set *bset; 377 struct blk_mq_tag_set *set; 378 struct request_queue *q; 379 int ret = -ENOMEM; 380 381 bset = kzalloc(sizeof(*bset), GFP_KERNEL); 382 if (!bset) 383 return ERR_PTR(-ENOMEM); 384 385 bset->job_fn = job_fn; 386 bset->timeout_fn = timeout; 387 388 set = &bset->tag_set; 389 set->ops = &bsg_mq_ops, 390 set->nr_hw_queues = 1; 391 set->queue_depth = 128; 392 set->numa_node = NUMA_NO_NODE; 393 set->cmd_size = sizeof(struct bsg_job) + dd_job_size; 394 set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING; 395 if (blk_mq_alloc_tag_set(set)) 396 goto out_tag_set; 397 398 q = blk_mq_init_queue(set); 399 if (IS_ERR(q)) { 400 ret = PTR_ERR(q); 401 goto out_queue; 402 } 403 404 q->queuedata = dev; 405 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); 406 407 ret = bsg_register_queue(q, dev, name, &bsg_transport_ops); 408 if (ret) { 409 printk(KERN_ERR "%s: bsg interface failed to " 410 "initialize - register queue\n", dev->kobj.name); 411 goto out_cleanup_queue; 412 } 413 414 return q; 415 out_cleanup_queue: 416 blk_cleanup_queue(q); 417 out_queue: 418 blk_mq_free_tag_set(set); 419 out_tag_set: 420 kfree(bset); 421 return ERR_PTR(ret); 422 } 423 EXPORT_SYMBOL_GPL(bsg_setup_queue); 424