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