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