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 bsg_job *job) 36 { 37 put_device(job->dev); /* release reference for the request */ 38 39 kfree(job->request_payload.sg_list); 40 kfree(job->reply_payload.sg_list); 41 kfree(job); 42 } 43 44 /** 45 * bsg_job_done - completion routine for bsg requests 46 * @job: bsg_job that is complete 47 * @result: job reply result 48 * @reply_payload_rcv_len: length of payload recvd 49 * 50 * The LLD should call this when the bsg job has completed. 51 */ 52 void bsg_job_done(struct bsg_job *job, int result, 53 unsigned int reply_payload_rcv_len) 54 { 55 struct request *req = job->req; 56 struct request *rsp = req->next_rq; 57 int err; 58 59 err = job->req->errors = result; 60 if (err < 0) 61 /* we're only returning the result field in the reply */ 62 job->req->sense_len = sizeof(u32); 63 else 64 job->req->sense_len = job->reply_len; 65 /* we assume all request payload was transferred, residual == 0 */ 66 req->resid_len = 0; 67 68 if (rsp) { 69 WARN_ON(reply_payload_rcv_len > rsp->resid_len); 70 71 /* set reply (bidi) residual */ 72 rsp->resid_len -= min(reply_payload_rcv_len, rsp->resid_len); 73 } 74 blk_complete_request(req); 75 } 76 EXPORT_SYMBOL_GPL(bsg_job_done); 77 78 /** 79 * bsg_softirq_done - softirq done routine for destroying the bsg requests 80 * @rq: BSG request that holds the job to be destroyed 81 */ 82 static void bsg_softirq_done(struct request *rq) 83 { 84 struct bsg_job *job = rq->special; 85 86 blk_end_request_all(rq, rq->errors); 87 bsg_destroy_job(job); 88 } 89 90 static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req) 91 { 92 size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments); 93 94 BUG_ON(!req->nr_phys_segments); 95 96 buf->sg_list = kzalloc(sz, GFP_KERNEL); 97 if (!buf->sg_list) 98 return -ENOMEM; 99 sg_init_table(buf->sg_list, req->nr_phys_segments); 100 buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list); 101 buf->payload_len = blk_rq_bytes(req); 102 return 0; 103 } 104 105 /** 106 * bsg_create_job - create the bsg_job structure for the bsg request 107 * @dev: device that is being sent the bsg request 108 * @req: BSG request that needs a job structure 109 */ 110 static int bsg_create_job(struct device *dev, struct request *req) 111 { 112 struct request *rsp = req->next_rq; 113 struct request_queue *q = req->q; 114 struct bsg_job *job; 115 int ret; 116 117 BUG_ON(req->special); 118 119 job = kzalloc(sizeof(struct bsg_job) + q->bsg_job_size, GFP_KERNEL); 120 if (!job) 121 return -ENOMEM; 122 123 req->special = job; 124 job->req = req; 125 if (q->bsg_job_size) 126 job->dd_data = (void *)&job[1]; 127 job->request = req->cmd; 128 job->request_len = req->cmd_len; 129 job->reply = req->sense; 130 job->reply_len = SCSI_SENSE_BUFFERSIZE; /* Size of sense buffer 131 * allocated */ 132 if (req->bio) { 133 ret = bsg_map_buffer(&job->request_payload, req); 134 if (ret) 135 goto failjob_rls_job; 136 } 137 if (rsp && rsp->bio) { 138 ret = bsg_map_buffer(&job->reply_payload, rsp); 139 if (ret) 140 goto failjob_rls_rqst_payload; 141 } 142 job->dev = dev; 143 /* take a reference for the request */ 144 get_device(job->dev); 145 return 0; 146 147 failjob_rls_rqst_payload: 148 kfree(job->request_payload.sg_list); 149 failjob_rls_job: 150 kfree(job); 151 return -ENOMEM; 152 } 153 154 /** 155 * bsg_request_fn - generic handler for bsg requests 156 * @q: request queue to manage 157 * 158 * On error the create_bsg_job function should return a -Exyz error value 159 * that will be set to the req->errors. 160 * 161 * Drivers/subsys should pass this to the queue init function. 162 */ 163 void bsg_request_fn(struct request_queue *q) 164 { 165 struct device *dev = q->queuedata; 166 struct request *req; 167 struct bsg_job *job; 168 int ret; 169 170 if (!get_device(dev)) 171 return; 172 173 while (1) { 174 req = blk_fetch_request(q); 175 if (!req) 176 break; 177 spin_unlock_irq(q->queue_lock); 178 179 ret = bsg_create_job(dev, req); 180 if (ret) { 181 req->errors = ret; 182 blk_end_request_all(req, ret); 183 spin_lock_irq(q->queue_lock); 184 continue; 185 } 186 187 job = req->special; 188 ret = q->bsg_job_fn(job); 189 spin_lock_irq(q->queue_lock); 190 if (ret) 191 break; 192 } 193 194 spin_unlock_irq(q->queue_lock); 195 put_device(dev); 196 spin_lock_irq(q->queue_lock); 197 } 198 EXPORT_SYMBOL_GPL(bsg_request_fn); 199 200 /** 201 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests 202 * @dev: device to attach bsg device to 203 * @q: request queue setup by caller 204 * @name: device to give bsg device 205 * @job_fn: bsg job handler 206 * @dd_job_size: size of LLD data needed for each job 207 * 208 * The caller should have setup the reuqest queue with bsg_request_fn 209 * as the request_fn. 210 */ 211 int bsg_setup_queue(struct device *dev, struct request_queue *q, 212 char *name, bsg_job_fn *job_fn, int dd_job_size) 213 { 214 int ret; 215 216 q->queuedata = dev; 217 q->bsg_job_size = dd_job_size; 218 q->bsg_job_fn = job_fn; 219 queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q); 220 blk_queue_softirq_done(q, bsg_softirq_done); 221 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); 222 223 ret = bsg_register_queue(q, dev, name, NULL); 224 if (ret) { 225 printk(KERN_ERR "%s: bsg interface failed to " 226 "initialize - register queue\n", dev->kobj.name); 227 return ret; 228 } 229 230 return 0; 231 } 232 EXPORT_SYMBOL_GPL(bsg_setup_queue); 233