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 31 /** 32 * bsg_teardown_job - routine to teardown a bsg job 33 * @kref: kref inside bsg_job that is to be torn down 34 */ 35 static void bsg_teardown_job(struct kref *kref) 36 { 37 struct bsg_job *job = container_of(kref, struct bsg_job, kref); 38 struct request *rq = job->req; 39 40 put_device(job->dev); /* release reference for the request */ 41 42 kfree(job->request_payload.sg_list); 43 kfree(job->reply_payload.sg_list); 44 45 blk_end_request_all(rq, BLK_STS_OK); 46 } 47 48 void bsg_job_put(struct bsg_job *job) 49 { 50 kref_put(&job->kref, bsg_teardown_job); 51 } 52 EXPORT_SYMBOL_GPL(bsg_job_put); 53 54 int bsg_job_get(struct bsg_job *job) 55 { 56 return kref_get_unless_zero(&job->kref); 57 } 58 EXPORT_SYMBOL_GPL(bsg_job_get); 59 60 /** 61 * bsg_job_done - completion routine for bsg requests 62 * @job: bsg_job that is complete 63 * @result: job reply result 64 * @reply_payload_rcv_len: length of payload recvd 65 * 66 * The LLD should call this when the bsg job has completed. 67 */ 68 void bsg_job_done(struct bsg_job *job, int result, 69 unsigned int reply_payload_rcv_len) 70 { 71 struct request *req = job->req; 72 struct request *rsp = req->next_rq; 73 struct scsi_request *rq = scsi_req(req); 74 int err; 75 76 err = scsi_req(job->req)->result = result; 77 if (err < 0) 78 /* we're only returning the result field in the reply */ 79 rq->sense_len = sizeof(u32); 80 else 81 rq->sense_len = job->reply_len; 82 /* we assume all request payload was transferred, residual == 0 */ 83 rq->resid_len = 0; 84 85 if (rsp) { 86 WARN_ON(reply_payload_rcv_len > scsi_req(rsp)->resid_len); 87 88 /* set reply (bidi) residual */ 89 scsi_req(rsp)->resid_len -= 90 min(reply_payload_rcv_len, scsi_req(rsp)->resid_len); 91 } 92 blk_complete_request(req); 93 } 94 EXPORT_SYMBOL_GPL(bsg_job_done); 95 96 /** 97 * bsg_softirq_done - softirq done routine for destroying the bsg requests 98 * @rq: BSG request that holds the job to be destroyed 99 */ 100 static void bsg_softirq_done(struct request *rq) 101 { 102 struct bsg_job *job = blk_mq_rq_to_pdu(rq); 103 104 bsg_job_put(job); 105 } 106 107 static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req) 108 { 109 size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments); 110 111 BUG_ON(!req->nr_phys_segments); 112 113 buf->sg_list = kzalloc(sz, GFP_KERNEL); 114 if (!buf->sg_list) 115 return -ENOMEM; 116 sg_init_table(buf->sg_list, req->nr_phys_segments); 117 scsi_req(req)->resid_len = blk_rq_bytes(req); 118 buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list); 119 buf->payload_len = blk_rq_bytes(req); 120 return 0; 121 } 122 123 /** 124 * bsg_prepare_job - create the bsg_job structure for the bsg request 125 * @dev: device that is being sent the bsg request 126 * @req: BSG request that needs a job structure 127 */ 128 static int bsg_prepare_job(struct device *dev, struct request *req) 129 { 130 struct request *rsp = req->next_rq; 131 struct scsi_request *rq = scsi_req(req); 132 struct bsg_job *job = blk_mq_rq_to_pdu(req); 133 int ret; 134 135 job->request = rq->cmd; 136 job->request_len = rq->cmd_len; 137 138 if (req->bio) { 139 ret = bsg_map_buffer(&job->request_payload, req); 140 if (ret) 141 goto failjob_rls_job; 142 } 143 if (rsp && rsp->bio) { 144 ret = bsg_map_buffer(&job->reply_payload, rsp); 145 if (ret) 146 goto failjob_rls_rqst_payload; 147 } 148 job->dev = dev; 149 /* take a reference for the request */ 150 get_device(job->dev); 151 kref_init(&job->kref); 152 return 0; 153 154 failjob_rls_rqst_payload: 155 kfree(job->request_payload.sg_list); 156 failjob_rls_job: 157 return -ENOMEM; 158 } 159 160 /** 161 * bsg_request_fn - generic handler for bsg requests 162 * @q: request queue to manage 163 * 164 * On error the create_bsg_job function should return a -Exyz error value 165 * that will be set to ->result. 166 * 167 * Drivers/subsys should pass this to the queue init function. 168 */ 169 static void bsg_request_fn(struct request_queue *q) 170 __releases(q->queue_lock) 171 __acquires(q->queue_lock) 172 { 173 struct device *dev = q->queuedata; 174 struct request *req; 175 int ret; 176 177 if (!get_device(dev)) 178 return; 179 180 while (1) { 181 req = blk_fetch_request(q); 182 if (!req) 183 break; 184 spin_unlock_irq(q->queue_lock); 185 186 ret = bsg_prepare_job(dev, req); 187 if (ret) { 188 scsi_req(req)->result = ret; 189 blk_end_request_all(req, BLK_STS_OK); 190 spin_lock_irq(q->queue_lock); 191 continue; 192 } 193 194 ret = q->bsg_job_fn(blk_mq_rq_to_pdu(req)); 195 spin_lock_irq(q->queue_lock); 196 if (ret) 197 break; 198 } 199 200 spin_unlock_irq(q->queue_lock); 201 put_device(dev); 202 spin_lock_irq(q->queue_lock); 203 } 204 205 static int bsg_init_rq(struct request_queue *q, struct request *req, gfp_t gfp) 206 { 207 struct bsg_job *job = blk_mq_rq_to_pdu(req); 208 struct scsi_request *sreq = &job->sreq; 209 210 /* called right after the request is allocated for the request_queue */ 211 212 sreq->sense = kzalloc(SCSI_SENSE_BUFFERSIZE, gfp); 213 if (!sreq->sense) 214 return -ENOMEM; 215 216 return 0; 217 } 218 219 static void bsg_initialize_rq(struct request *req) 220 { 221 struct bsg_job *job = blk_mq_rq_to_pdu(req); 222 struct scsi_request *sreq = &job->sreq; 223 void *sense = sreq->sense; 224 225 /* called right before the request is given to the request_queue user */ 226 227 memset(job, 0, sizeof(*job)); 228 229 scsi_req_init(sreq); 230 231 sreq->sense = sense; 232 sreq->sense_len = SCSI_SENSE_BUFFERSIZE; 233 234 job->req = req; 235 job->reply = sense; 236 job->reply_len = sreq->sense_len; 237 job->dd_data = job + 1; 238 } 239 240 static void bsg_exit_rq(struct request_queue *q, struct request *req) 241 { 242 struct bsg_job *job = blk_mq_rq_to_pdu(req); 243 struct scsi_request *sreq = &job->sreq; 244 245 kfree(sreq->sense); 246 } 247 248 /** 249 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests 250 * @dev: device to attach bsg device to 251 * @name: device to give bsg device 252 * @job_fn: bsg job handler 253 * @dd_job_size: size of LLD data needed for each job 254 * @release: @dev release function 255 */ 256 struct request_queue *bsg_setup_queue(struct device *dev, const char *name, 257 bsg_job_fn *job_fn, int dd_job_size, 258 void (*release)(struct device *)) 259 { 260 struct request_queue *q; 261 int ret; 262 263 q = blk_alloc_queue(GFP_KERNEL); 264 if (!q) 265 return ERR_PTR(-ENOMEM); 266 q->cmd_size = sizeof(struct bsg_job) + dd_job_size; 267 q->init_rq_fn = bsg_init_rq; 268 q->exit_rq_fn = bsg_exit_rq; 269 q->initialize_rq_fn = bsg_initialize_rq; 270 q->request_fn = bsg_request_fn; 271 272 ret = blk_init_allocated_queue(q); 273 if (ret) 274 goto out_cleanup_queue; 275 276 q->queuedata = dev; 277 q->bsg_job_fn = job_fn; 278 queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q); 279 queue_flag_set_unlocked(QUEUE_FLAG_SCSI_PASSTHROUGH, q); 280 blk_queue_softirq_done(q, bsg_softirq_done); 281 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); 282 283 ret = bsg_register_queue(q, dev, name, release); 284 if (ret) { 285 printk(KERN_ERR "%s: bsg interface failed to " 286 "initialize - register queue\n", dev->kobj.name); 287 goto out_cleanup_queue; 288 } 289 290 return q; 291 out_cleanup_queue: 292 blk_cleanup_queue(q); 293 return ERR_PTR(ret); 294 } 295 EXPORT_SYMBOL_GPL(bsg_setup_queue); 296