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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 */
35static 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 */
52void 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}
76EXPORT_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 */
82static 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
90static 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 */
110static 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
147failjob_rls_rqst_payload:
148 kfree(job->request_payload.sg_list);
149failjob_rls_job:
150 kfree(job);
151 return -ENOMEM;
152}
153
154/*
155 * bsg_goose_queue - restart queue in case it was stopped
156 * @q: request q to be restarted
157 */
158void bsg_goose_queue(struct request_queue *q)
159{
160 if (!q)
161 return;
162
163 blk_run_queue_async(q);
164}
165EXPORT_SYMBOL_GPL(bsg_goose_queue);
166
167/**
168 * bsg_request_fn - generic handler for bsg requests
169 * @q: request queue to manage
170 *
171 * On error the create_bsg_job function should return a -Exyz error value
172 * that will be set to the req->errors.
173 *
174 * Drivers/subsys should pass this to the queue init function.
175 */
176void bsg_request_fn(struct request_queue *q)
177{
178 struct device *dev = q->queuedata;
179 struct request *req;
180 struct bsg_job *job;
181 int ret;
182
183 if (!get_device(dev))
184 return;
185
186 while (1) {
187 req = blk_fetch_request(q);
188 if (!req)
189 break;
190 spin_unlock_irq(q->queue_lock);
191
192 ret = bsg_create_job(dev, req);
193 if (ret) {
194 req->errors = ret;
195 blk_end_request_all(req, ret);
196 spin_lock_irq(q->queue_lock);
197 continue;
198 }
199
200 job = req->special;
201 ret = q->bsg_job_fn(job);
202 spin_lock_irq(q->queue_lock);
203 if (ret)
204 break;
205 }
206
207 spin_unlock_irq(q->queue_lock);
208 put_device(dev);
209 spin_lock_irq(q->queue_lock);
210}
211EXPORT_SYMBOL_GPL(bsg_request_fn);
212
213/**
214 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
215 * @dev: device to attach bsg device to
216 * @q: request queue setup by caller
217 * @name: device to give bsg device
218 * @job_fn: bsg job handler
219 * @dd_job_size: size of LLD data needed for each job
220 *
221 * The caller should have setup the reuqest queue with bsg_request_fn
222 * as the request_fn.
223 */
224int bsg_setup_queue(struct device *dev, struct request_queue *q,
225 char *name, bsg_job_fn *job_fn, int dd_job_size)
226{
227 int ret;
228
229 q->queuedata = dev;
230 q->bsg_job_size = dd_job_size;
231 q->bsg_job_fn = job_fn;
232 queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q);
233 blk_queue_softirq_done(q, bsg_softirq_done);
234 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
235
236 ret = bsg_register_queue(q, dev, name, NULL);
237 if (ret) {
238 printk(KERN_ERR "%s: bsg interface failed to "
239 "initialize - register queue\n", dev->kobj.name);
240 return ret;
241 }
242
243 return 0;
244}
245EXPORT_SYMBOL_GPL(bsg_setup_queue);
246
247/**
248 * bsg_remove_queue - Deletes the bsg dev from the q
249 * @q: the request_queue that is to be torn down.
250 *
251 * Notes:
252 * Before unregistering the queue empty any requests that are blocked
253 */
254void bsg_remove_queue(struct request_queue *q)
255{
256 struct request *req; /* block request */
257 int counts; /* totals for request_list count and starved */
258
259 if (!q)
260 return;
261
262 /* Stop taking in new requests */
263 spin_lock_irq(q->queue_lock);
264 blk_stop_queue(q);
265
266 /* drain all requests in the queue */
267 while (1) {
268 /* need the lock to fetch a request
269 * this may fetch the same reqeust as the previous pass
270 */
271 req = blk_fetch_request(q);
272 /* save requests in use and starved */
273 counts = q->rq.count[0] + q->rq.count[1] +
274 q->rq.starved[0] + q->rq.starved[1];
275 spin_unlock_irq(q->queue_lock);
276 /* any requests still outstanding? */
277 if (counts == 0)
278 break;
279
280 /* This may be the same req as the previous iteration,
281 * always send the blk_end_request_all after a prefetch.
282 * It is not okay to not end the request because the
283 * prefetch started the request.
284 */
285 if (req) {
286 /* return -ENXIO to indicate that this queue is
287 * going away
288 */
289 req->errors = -ENXIO;
290 blk_end_request_all(req, -ENXIO);
291 }
292
293 msleep(200); /* allow bsg to possibly finish */
294 spin_lock_irq(q->queue_lock);
295 }
296 bsg_unregister_queue(q);
297}
298EXPORT_SYMBOL_GPL(bsg_remove_queue);
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/module.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 */
35static 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 */
52void 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}
76EXPORT_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 */
82static 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
90static 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 */
110static 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
147failjob_rls_rqst_payload:
148 kfree(job->request_payload.sg_list);
149failjob_rls_job:
150 kfree(job);
151 return -ENOMEM;
152}
153
154/*
155 * bsg_goose_queue - restart queue in case it was stopped
156 * @q: request q to be restarted
157 */
158void bsg_goose_queue(struct request_queue *q)
159{
160 if (!q)
161 return;
162
163 blk_run_queue_async(q);
164}
165EXPORT_SYMBOL_GPL(bsg_goose_queue);
166
167/**
168 * bsg_request_fn - generic handler for bsg requests
169 * @q: request queue to manage
170 *
171 * On error the create_bsg_job function should return a -Exyz error value
172 * that will be set to the req->errors.
173 *
174 * Drivers/subsys should pass this to the queue init function.
175 */
176void bsg_request_fn(struct request_queue *q)
177{
178 struct device *dev = q->queuedata;
179 struct request *req;
180 struct bsg_job *job;
181 int ret;
182
183 if (!get_device(dev))
184 return;
185
186 while (1) {
187 req = blk_fetch_request(q);
188 if (!req)
189 break;
190 spin_unlock_irq(q->queue_lock);
191
192 ret = bsg_create_job(dev, req);
193 if (ret) {
194 req->errors = ret;
195 blk_end_request_all(req, ret);
196 spin_lock_irq(q->queue_lock);
197 continue;
198 }
199
200 job = req->special;
201 ret = q->bsg_job_fn(job);
202 spin_lock_irq(q->queue_lock);
203 if (ret)
204 break;
205 }
206
207 spin_unlock_irq(q->queue_lock);
208 put_device(dev);
209 spin_lock_irq(q->queue_lock);
210}
211EXPORT_SYMBOL_GPL(bsg_request_fn);
212
213/**
214 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
215 * @dev: device to attach bsg device to
216 * @q: request queue setup by caller
217 * @name: device to give bsg device
218 * @job_fn: bsg job handler
219 * @dd_job_size: size of LLD data needed for each job
220 *
221 * The caller should have setup the reuqest queue with bsg_request_fn
222 * as the request_fn.
223 */
224int bsg_setup_queue(struct device *dev, struct request_queue *q,
225 char *name, bsg_job_fn *job_fn, int dd_job_size)
226{
227 int ret;
228
229 q->queuedata = dev;
230 q->bsg_job_size = dd_job_size;
231 q->bsg_job_fn = job_fn;
232 queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q);
233 blk_queue_softirq_done(q, bsg_softirq_done);
234 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
235
236 ret = bsg_register_queue(q, dev, name, NULL);
237 if (ret) {
238 printk(KERN_ERR "%s: bsg interface failed to "
239 "initialize - register queue\n", dev->kobj.name);
240 return ret;
241 }
242
243 return 0;
244}
245EXPORT_SYMBOL_GPL(bsg_setup_queue);
246
247/**
248 * bsg_remove_queue - Deletes the bsg dev from the q
249 * @q: the request_queue that is to be torn down.
250 *
251 * Notes:
252 * Before unregistering the queue empty any requests that are blocked
253 */
254void bsg_remove_queue(struct request_queue *q)
255{
256 struct request *req; /* block request */
257 int counts; /* totals for request_list count and starved */
258
259 if (!q)
260 return;
261
262 /* Stop taking in new requests */
263 spin_lock_irq(q->queue_lock);
264 blk_stop_queue(q);
265
266 /* drain all requests in the queue */
267 while (1) {
268 /* need the lock to fetch a request
269 * this may fetch the same reqeust as the previous pass
270 */
271 req = blk_fetch_request(q);
272 /* save requests in use and starved */
273 counts = q->rq.count[0] + q->rq.count[1] +
274 q->rq.starved[0] + q->rq.starved[1];
275 spin_unlock_irq(q->queue_lock);
276 /* any requests still outstanding? */
277 if (counts == 0)
278 break;
279
280 /* This may be the same req as the previous iteration,
281 * always send the blk_end_request_all after a prefetch.
282 * It is not okay to not end the request because the
283 * prefetch started the request.
284 */
285 if (req) {
286 /* return -ENXIO to indicate that this queue is
287 * going away
288 */
289 req->errors = -ENXIO;
290 blk_end_request_all(req, -ENXIO);
291 }
292
293 msleep(200); /* allow bsg to possibly finish */
294 spin_lock_irq(q->queue_lock);
295 }
296 bsg_unregister_queue(q);
297}
298EXPORT_SYMBOL_GPL(bsg_remove_queue);