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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_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 */
163void 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}
198EXPORT_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 */
211int 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}
232EXPORT_SYMBOL_GPL(bsg_setup_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/export.h>
29#include <scsi/scsi_cmnd.h>
30#include <scsi/sg.h>
31
32#define uptr64(val) ((void __user *)(uintptr_t)(val))
33
34static int bsg_transport_check_proto(struct sg_io_v4 *hdr)
35{
36 if (hdr->protocol != BSG_PROTOCOL_SCSI ||
37 hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_TRANSPORT)
38 return -EINVAL;
39 if (!capable(CAP_SYS_RAWIO))
40 return -EPERM;
41 return 0;
42}
43
44static int bsg_transport_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
45 fmode_t mode)
46{
47 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
48
49 job->request_len = hdr->request_len;
50 job->request = memdup_user(uptr64(hdr->request), hdr->request_len);
51 if (IS_ERR(job->request))
52 return PTR_ERR(job->request);
53 return 0;
54}
55
56static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
57{
58 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
59 int ret = 0;
60
61 /*
62 * The assignments below don't make much sense, but are kept for
63 * bug by bug backwards compatibility:
64 */
65 hdr->device_status = job->result & 0xff;
66 hdr->transport_status = host_byte(job->result);
67 hdr->driver_status = driver_byte(job->result);
68 hdr->info = 0;
69 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
70 hdr->info |= SG_INFO_CHECK;
71 hdr->response_len = 0;
72
73 if (job->result < 0) {
74 /* we're only returning the result field in the reply */
75 job->reply_len = sizeof(u32);
76 ret = job->result;
77 }
78
79 if (job->reply_len && hdr->response) {
80 int len = min(hdr->max_response_len, job->reply_len);
81
82 if (copy_to_user(uptr64(hdr->response), job->reply, len))
83 ret = -EFAULT;
84 else
85 hdr->response_len = len;
86 }
87
88 /* we assume all request payload was transferred, residual == 0 */
89 hdr->dout_resid = 0;
90
91 if (rq->next_rq) {
92 unsigned int rsp_len = job->reply_payload.payload_len;
93
94 if (WARN_ON(job->reply_payload_rcv_len > rsp_len))
95 hdr->din_resid = 0;
96 else
97 hdr->din_resid = rsp_len - job->reply_payload_rcv_len;
98 } else {
99 hdr->din_resid = 0;
100 }
101
102 return ret;
103}
104
105static void bsg_transport_free_rq(struct request *rq)
106{
107 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
108
109 kfree(job->request);
110}
111
112static const struct bsg_ops bsg_transport_ops = {
113 .check_proto = bsg_transport_check_proto,
114 .fill_hdr = bsg_transport_fill_hdr,
115 .complete_rq = bsg_transport_complete_rq,
116 .free_rq = bsg_transport_free_rq,
117};
118
119/**
120 * bsg_teardown_job - routine to teardown a bsg job
121 * @kref: kref inside bsg_job that is to be torn down
122 */
123static void bsg_teardown_job(struct kref *kref)
124{
125 struct bsg_job *job = container_of(kref, struct bsg_job, kref);
126 struct request *rq = blk_mq_rq_from_pdu(job);
127
128 put_device(job->dev); /* release reference for the request */
129
130 kfree(job->request_payload.sg_list);
131 kfree(job->reply_payload.sg_list);
132
133 blk_end_request_all(rq, BLK_STS_OK);
134}
135
136void bsg_job_put(struct bsg_job *job)
137{
138 kref_put(&job->kref, bsg_teardown_job);
139}
140EXPORT_SYMBOL_GPL(bsg_job_put);
141
142int bsg_job_get(struct bsg_job *job)
143{
144 return kref_get_unless_zero(&job->kref);
145}
146EXPORT_SYMBOL_GPL(bsg_job_get);
147
148/**
149 * bsg_job_done - completion routine for bsg requests
150 * @job: bsg_job that is complete
151 * @result: job reply result
152 * @reply_payload_rcv_len: length of payload recvd
153 *
154 * The LLD should call this when the bsg job has completed.
155 */
156void bsg_job_done(struct bsg_job *job, int result,
157 unsigned int reply_payload_rcv_len)
158{
159 job->result = result;
160 job->reply_payload_rcv_len = reply_payload_rcv_len;
161 blk_complete_request(blk_mq_rq_from_pdu(job));
162}
163EXPORT_SYMBOL_GPL(bsg_job_done);
164
165/**
166 * bsg_softirq_done - softirq done routine for destroying the bsg requests
167 * @rq: BSG request that holds the job to be destroyed
168 */
169static void bsg_softirq_done(struct request *rq)
170{
171 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
172
173 bsg_job_put(job);
174}
175
176static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
177{
178 size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
179
180 BUG_ON(!req->nr_phys_segments);
181
182 buf->sg_list = kzalloc(sz, GFP_KERNEL);
183 if (!buf->sg_list)
184 return -ENOMEM;
185 sg_init_table(buf->sg_list, req->nr_phys_segments);
186 buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
187 buf->payload_len = blk_rq_bytes(req);
188 return 0;
189}
190
191/**
192 * bsg_prepare_job - create the bsg_job structure for the bsg request
193 * @dev: device that is being sent the bsg request
194 * @req: BSG request that needs a job structure
195 */
196static bool bsg_prepare_job(struct device *dev, struct request *req)
197{
198 struct request *rsp = req->next_rq;
199 struct bsg_job *job = blk_mq_rq_to_pdu(req);
200 int ret;
201
202 job->timeout = req->timeout;
203
204 if (req->bio) {
205 ret = bsg_map_buffer(&job->request_payload, req);
206 if (ret)
207 goto failjob_rls_job;
208 }
209 if (rsp && rsp->bio) {
210 ret = bsg_map_buffer(&job->reply_payload, rsp);
211 if (ret)
212 goto failjob_rls_rqst_payload;
213 }
214 job->dev = dev;
215 /* take a reference for the request */
216 get_device(job->dev);
217 kref_init(&job->kref);
218 return true;
219
220failjob_rls_rqst_payload:
221 kfree(job->request_payload.sg_list);
222failjob_rls_job:
223 job->result = -ENOMEM;
224 return false;
225}
226
227/**
228 * bsg_request_fn - generic handler for bsg requests
229 * @q: request queue to manage
230 *
231 * On error the create_bsg_job function should return a -Exyz error value
232 * that will be set to ->result.
233 *
234 * Drivers/subsys should pass this to the queue init function.
235 */
236static void bsg_request_fn(struct request_queue *q)
237 __releases(q->queue_lock)
238 __acquires(q->queue_lock)
239{
240 struct device *dev = q->queuedata;
241 struct request *req;
242 int ret;
243
244 if (!get_device(dev))
245 return;
246
247 while (1) {
248 req = blk_fetch_request(q);
249 if (!req)
250 break;
251 spin_unlock_irq(q->queue_lock);
252
253 if (!bsg_prepare_job(dev, req)) {
254 blk_end_request_all(req, BLK_STS_OK);
255 spin_lock_irq(q->queue_lock);
256 continue;
257 }
258
259 ret = q->bsg_job_fn(blk_mq_rq_to_pdu(req));
260 spin_lock_irq(q->queue_lock);
261 if (ret)
262 break;
263 }
264
265 spin_unlock_irq(q->queue_lock);
266 put_device(dev);
267 spin_lock_irq(q->queue_lock);
268}
269
270/* called right after the request is allocated for the request_queue */
271static int bsg_init_rq(struct request_queue *q, struct request *req, gfp_t gfp)
272{
273 struct bsg_job *job = blk_mq_rq_to_pdu(req);
274
275 job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, gfp);
276 if (!job->reply)
277 return -ENOMEM;
278 return 0;
279}
280
281/* called right before the request is given to the request_queue user */
282static void bsg_initialize_rq(struct request *req)
283{
284 struct bsg_job *job = blk_mq_rq_to_pdu(req);
285 void *reply = job->reply;
286
287 memset(job, 0, sizeof(*job));
288 job->reply = reply;
289 job->reply_len = SCSI_SENSE_BUFFERSIZE;
290 job->dd_data = job + 1;
291}
292
293static void bsg_exit_rq(struct request_queue *q, struct request *req)
294{
295 struct bsg_job *job = blk_mq_rq_to_pdu(req);
296
297 kfree(job->reply);
298}
299
300/**
301 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
302 * @dev: device to attach bsg device to
303 * @name: device to give bsg device
304 * @job_fn: bsg job handler
305 * @dd_job_size: size of LLD data needed for each job
306 * @release: @dev release function
307 */
308struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
309 bsg_job_fn *job_fn, int dd_job_size,
310 void (*release)(struct device *))
311{
312 struct request_queue *q;
313 int ret;
314
315 q = blk_alloc_queue(GFP_KERNEL);
316 if (!q)
317 return ERR_PTR(-ENOMEM);
318 q->cmd_size = sizeof(struct bsg_job) + dd_job_size;
319 q->init_rq_fn = bsg_init_rq;
320 q->exit_rq_fn = bsg_exit_rq;
321 q->initialize_rq_fn = bsg_initialize_rq;
322 q->request_fn = bsg_request_fn;
323
324 ret = blk_init_allocated_queue(q);
325 if (ret)
326 goto out_cleanup_queue;
327
328 q->queuedata = dev;
329 q->bsg_job_fn = job_fn;
330 blk_queue_flag_set(QUEUE_FLAG_BIDI, q);
331 blk_queue_softirq_done(q, bsg_softirq_done);
332 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
333
334 ret = bsg_register_queue(q, dev, name, &bsg_transport_ops, release);
335 if (ret) {
336 printk(KERN_ERR "%s: bsg interface failed to "
337 "initialize - register queue\n", dev->kobj.name);
338 goto out_cleanup_queue;
339 }
340
341 return q;
342out_cleanup_queue:
343 blk_cleanup_queue(q);
344 return ERR_PTR(ret);
345}
346EXPORT_SYMBOL_GPL(bsg_setup_queue);