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/blkdev.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 static int bsg_transport_check_proto(struct sg_io_v4 *hdr) 35 { 36 if (hdr->protocol != BSG_PROTOCOL_SCSI || 37 hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_TRANSPORT) 38 return -EINVAL; 39 if (!capable(CAP_SYS_RAWIO)) 40 return -EPERM; 41 return 0; 42 } 43 44 static int bsg_transport_fill_hdr(struct request *rq, struct sg_io_v4 *hdr, 45 fmode_t mode) 46 { 47 struct bsg_job *job = blk_mq_rq_to_pdu(rq); 48 49 job->request_len = hdr->request_len; 50 job->request = memdup_user(uptr64(hdr->request), hdr->request_len); 51 if (IS_ERR(job->request)) 52 return PTR_ERR(job->request); 53 return 0; 54 } 55 56 static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr) 57 { 58 struct bsg_job *job = blk_mq_rq_to_pdu(rq); 59 int ret = 0; 60 61 /* 62 * The assignments below don't make much sense, but are kept for 63 * bug by bug backwards compatibility: 64 */ 65 hdr->device_status = job->result & 0xff; 66 hdr->transport_status = host_byte(job->result); 67 hdr->driver_status = driver_byte(job->result); 68 hdr->info = 0; 69 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 70 hdr->info |= SG_INFO_CHECK; 71 hdr->response_len = 0; 72 73 if (job->result < 0) { 74 /* we're only returning the result field in the reply */ 75 job->reply_len = sizeof(u32); 76 ret = job->result; 77 } 78 79 if (job->reply_len && hdr->response) { 80 int len = min(hdr->max_response_len, job->reply_len); 81 82 if (copy_to_user(uptr64(hdr->response), job->reply, len)) 83 ret = -EFAULT; 84 else 85 hdr->response_len = len; 86 } 87 88 /* we assume all request payload was transferred, residual == 0 */ 89 hdr->dout_resid = 0; 90 91 if (rq->next_rq) { 92 unsigned int rsp_len = job->reply_payload.payload_len; 93 94 if (WARN_ON(job->reply_payload_rcv_len > rsp_len)) 95 hdr->din_resid = 0; 96 else 97 hdr->din_resid = rsp_len - job->reply_payload_rcv_len; 98 } else { 99 hdr->din_resid = 0; 100 } 101 102 return ret; 103 } 104 105 static void bsg_transport_free_rq(struct request *rq) 106 { 107 struct bsg_job *job = blk_mq_rq_to_pdu(rq); 108 109 kfree(job->request); 110 } 111 112 static const struct bsg_ops bsg_transport_ops = { 113 .check_proto = bsg_transport_check_proto, 114 .fill_hdr = bsg_transport_fill_hdr, 115 .complete_rq = bsg_transport_complete_rq, 116 .free_rq = bsg_transport_free_rq, 117 }; 118 119 /** 120 * bsg_teardown_job - routine to teardown a bsg job 121 * @kref: kref inside bsg_job that is to be torn down 122 */ 123 static void bsg_teardown_job(struct kref *kref) 124 { 125 struct bsg_job *job = container_of(kref, struct bsg_job, kref); 126 struct request *rq = blk_mq_rq_from_pdu(job); 127 128 put_device(job->dev); /* release reference for the request */ 129 130 kfree(job->request_payload.sg_list); 131 kfree(job->reply_payload.sg_list); 132 133 blk_end_request_all(rq, BLK_STS_OK); 134 } 135 136 void bsg_job_put(struct bsg_job *job) 137 { 138 kref_put(&job->kref, bsg_teardown_job); 139 } 140 EXPORT_SYMBOL_GPL(bsg_job_put); 141 142 int bsg_job_get(struct bsg_job *job) 143 { 144 return kref_get_unless_zero(&job->kref); 145 } 146 EXPORT_SYMBOL_GPL(bsg_job_get); 147 148 /** 149 * bsg_job_done - completion routine for bsg requests 150 * @job: bsg_job that is complete 151 * @result: job reply result 152 * @reply_payload_rcv_len: length of payload recvd 153 * 154 * The LLD should call this when the bsg job has completed. 155 */ 156 void bsg_job_done(struct bsg_job *job, int result, 157 unsigned int reply_payload_rcv_len) 158 { 159 job->result = result; 160 job->reply_payload_rcv_len = reply_payload_rcv_len; 161 blk_complete_request(blk_mq_rq_from_pdu(job)); 162 } 163 EXPORT_SYMBOL_GPL(bsg_job_done); 164 165 /** 166 * bsg_softirq_done - softirq done routine for destroying the bsg requests 167 * @rq: BSG request that holds the job to be destroyed 168 */ 169 static void bsg_softirq_done(struct request *rq) 170 { 171 struct bsg_job *job = blk_mq_rq_to_pdu(rq); 172 173 bsg_job_put(job); 174 } 175 176 static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req) 177 { 178 size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments); 179 180 BUG_ON(!req->nr_phys_segments); 181 182 buf->sg_list = kzalloc(sz, GFP_KERNEL); 183 if (!buf->sg_list) 184 return -ENOMEM; 185 sg_init_table(buf->sg_list, req->nr_phys_segments); 186 buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list); 187 buf->payload_len = blk_rq_bytes(req); 188 return 0; 189 } 190 191 /** 192 * bsg_prepare_job - create the bsg_job structure for the bsg request 193 * @dev: device that is being sent the bsg request 194 * @req: BSG request that needs a job structure 195 */ 196 static bool bsg_prepare_job(struct device *dev, struct request *req) 197 { 198 struct request *rsp = req->next_rq; 199 struct bsg_job *job = blk_mq_rq_to_pdu(req); 200 int ret; 201 202 job->timeout = req->timeout; 203 204 if (req->bio) { 205 ret = bsg_map_buffer(&job->request_payload, req); 206 if (ret) 207 goto failjob_rls_job; 208 } 209 if (rsp && rsp->bio) { 210 ret = bsg_map_buffer(&job->reply_payload, rsp); 211 if (ret) 212 goto failjob_rls_rqst_payload; 213 } 214 job->dev = dev; 215 /* take a reference for the request */ 216 get_device(job->dev); 217 kref_init(&job->kref); 218 return true; 219 220 failjob_rls_rqst_payload: 221 kfree(job->request_payload.sg_list); 222 failjob_rls_job: 223 job->result = -ENOMEM; 224 return false; 225 } 226 227 /** 228 * bsg_request_fn - generic handler for bsg requests 229 * @q: request queue to manage 230 * 231 * On error the create_bsg_job function should return a -Exyz error value 232 * that will be set to ->result. 233 * 234 * Drivers/subsys should pass this to the queue init function. 235 */ 236 static void bsg_request_fn(struct request_queue *q) 237 __releases(q->queue_lock) 238 __acquires(q->queue_lock) 239 { 240 struct device *dev = q->queuedata; 241 struct request *req; 242 int ret; 243 244 if (!get_device(dev)) 245 return; 246 247 while (1) { 248 req = blk_fetch_request(q); 249 if (!req) 250 break; 251 spin_unlock_irq(q->queue_lock); 252 253 if (!bsg_prepare_job(dev, req)) { 254 blk_end_request_all(req, BLK_STS_OK); 255 spin_lock_irq(q->queue_lock); 256 continue; 257 } 258 259 ret = q->bsg_job_fn(blk_mq_rq_to_pdu(req)); 260 spin_lock_irq(q->queue_lock); 261 if (ret) 262 break; 263 } 264 265 spin_unlock_irq(q->queue_lock); 266 put_device(dev); 267 spin_lock_irq(q->queue_lock); 268 } 269 270 /* called right after the request is allocated for the request_queue */ 271 static int bsg_init_rq(struct request_queue *q, struct request *req, gfp_t gfp) 272 { 273 struct bsg_job *job = blk_mq_rq_to_pdu(req); 274 275 job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, gfp); 276 if (!job->reply) 277 return -ENOMEM; 278 return 0; 279 } 280 281 /* called right before the request is given to the request_queue user */ 282 static void bsg_initialize_rq(struct request *req) 283 { 284 struct bsg_job *job = blk_mq_rq_to_pdu(req); 285 void *reply = job->reply; 286 287 memset(job, 0, sizeof(*job)); 288 job->reply = reply; 289 job->reply_len = SCSI_SENSE_BUFFERSIZE; 290 job->dd_data = job + 1; 291 } 292 293 static void bsg_exit_rq(struct request_queue *q, struct request *req) 294 { 295 struct bsg_job *job = blk_mq_rq_to_pdu(req); 296 297 kfree(job->reply); 298 } 299 300 /** 301 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests 302 * @dev: device to attach bsg device to 303 * @name: device to give bsg device 304 * @job_fn: bsg job handler 305 * @dd_job_size: size of LLD data needed for each job 306 * @release: @dev release function 307 */ 308 struct request_queue *bsg_setup_queue(struct device *dev, const char *name, 309 bsg_job_fn *job_fn, int dd_job_size, 310 void (*release)(struct device *)) 311 { 312 struct request_queue *q; 313 int ret; 314 315 q = blk_alloc_queue(GFP_KERNEL); 316 if (!q) 317 return ERR_PTR(-ENOMEM); 318 q->cmd_size = sizeof(struct bsg_job) + dd_job_size; 319 q->init_rq_fn = bsg_init_rq; 320 q->exit_rq_fn = bsg_exit_rq; 321 q->initialize_rq_fn = bsg_initialize_rq; 322 q->request_fn = bsg_request_fn; 323 324 ret = blk_init_allocated_queue(q); 325 if (ret) 326 goto out_cleanup_queue; 327 328 q->queuedata = dev; 329 q->bsg_job_fn = job_fn; 330 blk_queue_flag_set(QUEUE_FLAG_BIDI, q); 331 blk_queue_softirq_done(q, bsg_softirq_done); 332 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); 333 334 ret = bsg_register_queue(q, dev, name, &bsg_transport_ops, release); 335 if (ret) { 336 printk(KERN_ERR "%s: bsg interface failed to " 337 "initialize - register queue\n", dev->kobj.name); 338 goto out_cleanup_queue; 339 } 340 341 return q; 342 out_cleanup_queue: 343 blk_cleanup_queue(q); 344 return ERR_PTR(ret); 345 } 346 EXPORT_SYMBOL_GPL(bsg_setup_queue); 347