Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/block/bsg-lib.c

  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 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us