Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
[linux-2.6-block.git] / block / bsg-lib.c
CommitLineData
aa387cc8
MC
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>
6adb1236 28#include <linux/export.h>
aa387cc8 29#include <scsi/scsi_cmnd.h>
17cb960f
CH
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);
47255491 51
52 return PTR_ERR_OR_ZERO(job->request);
17cb960f
CH
53}
54
55static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
56{
57 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
58 int ret = 0;
59
60 /*
61 * The assignments below don't make much sense, but are kept for
62 * bug by bug backwards compatibility:
63 */
64 hdr->device_status = job->result & 0xff;
65 hdr->transport_status = host_byte(job->result);
66 hdr->driver_status = driver_byte(job->result);
67 hdr->info = 0;
68 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
69 hdr->info |= SG_INFO_CHECK;
70 hdr->response_len = 0;
71
72 if (job->result < 0) {
73 /* we're only returning the result field in the reply */
74 job->reply_len = sizeof(u32);
75 ret = job->result;
76 }
77
78 if (job->reply_len && hdr->response) {
79 int len = min(hdr->max_response_len, job->reply_len);
80
81 if (copy_to_user(uptr64(hdr->response), job->reply, len))
82 ret = -EFAULT;
83 else
84 hdr->response_len = len;
85 }
86
87 /* we assume all request payload was transferred, residual == 0 */
88 hdr->dout_resid = 0;
89
90 if (rq->next_rq) {
91 unsigned int rsp_len = job->reply_payload.payload_len;
92
93 if (WARN_ON(job->reply_payload_rcv_len > rsp_len))
94 hdr->din_resid = 0;
95 else
96 hdr->din_resid = rsp_len - job->reply_payload_rcv_len;
97 } else {
98 hdr->din_resid = 0;
99 }
100
101 return ret;
102}
103
104static void bsg_transport_free_rq(struct request *rq)
105{
106 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
107
108 kfree(job->request);
109}
110
111static const struct bsg_ops bsg_transport_ops = {
112 .check_proto = bsg_transport_check_proto,
113 .fill_hdr = bsg_transport_fill_hdr,
114 .complete_rq = bsg_transport_complete_rq,
115 .free_rq = bsg_transport_free_rq,
116};
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MC
117
118/**
50b4d485 119 * bsg_teardown_job - routine to teardown a bsg job
aa98192d 120 * @kref: kref inside bsg_job that is to be torn down
aa387cc8 121 */
50b4d485 122static void bsg_teardown_job(struct kref *kref)
aa387cc8 123{
bf0f2d38 124 struct bsg_job *job = container_of(kref, struct bsg_job, kref);
ef6fa64f 125 struct request *rq = blk_mq_rq_from_pdu(job);
c00da4c9 126
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MC
127 put_device(job->dev); /* release reference for the request */
128
129 kfree(job->request_payload.sg_list);
130 kfree(job->reply_payload.sg_list);
50b4d485
BB
131
132 blk_end_request_all(rq, BLK_STS_OK);
aa387cc8
MC
133}
134
fb6f7c8d
JT
135void bsg_job_put(struct bsg_job *job)
136{
50b4d485 137 kref_put(&job->kref, bsg_teardown_job);
fb6f7c8d
JT
138}
139EXPORT_SYMBOL_GPL(bsg_job_put);
140
141int bsg_job_get(struct bsg_job *job)
142{
143 return kref_get_unless_zero(&job->kref);
144}
145EXPORT_SYMBOL_GPL(bsg_job_get);
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MC
146
147/**
148 * bsg_job_done - completion routine for bsg requests
149 * @job: bsg_job that is complete
150 * @result: job reply result
151 * @reply_payload_rcv_len: length of payload recvd
152 *
153 * The LLD should call this when the bsg job has completed.
154 */
155void bsg_job_done(struct bsg_job *job, int result,
156 unsigned int reply_payload_rcv_len)
157{
17cb960f
CH
158 job->result = result;
159 job->reply_payload_rcv_len = reply_payload_rcv_len;
160 blk_complete_request(blk_mq_rq_from_pdu(job));
aa387cc8
MC
161}
162EXPORT_SYMBOL_GPL(bsg_job_done);
163
164/**
165 * bsg_softirq_done - softirq done routine for destroying the bsg requests
166 * @rq: BSG request that holds the job to be destroyed
167 */
168static void bsg_softirq_done(struct request *rq)
169{
50b4d485 170 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
aa387cc8 171
fb6f7c8d 172 bsg_job_put(job);
aa387cc8
MC
173}
174
175static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
176{
177 size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
178
179 BUG_ON(!req->nr_phys_segments);
180
181 buf->sg_list = kzalloc(sz, GFP_KERNEL);
182 if (!buf->sg_list)
183 return -ENOMEM;
184 sg_init_table(buf->sg_list, req->nr_phys_segments);
185 buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
186 buf->payload_len = blk_rq_bytes(req);
187 return 0;
188}
189
190/**
50b4d485 191 * bsg_prepare_job - create the bsg_job structure for the bsg request
aa387cc8
MC
192 * @dev: device that is being sent the bsg request
193 * @req: BSG request that needs a job structure
194 */
17cb960f 195static bool bsg_prepare_job(struct device *dev, struct request *req)
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MC
196{
197 struct request *rsp = req->next_rq;
50b4d485 198 struct bsg_job *job = blk_mq_rq_to_pdu(req);
aa387cc8
MC
199 int ret;
200
31156ec3 201 job->timeout = req->timeout;
50b4d485 202
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MC
203 if (req->bio) {
204 ret = bsg_map_buffer(&job->request_payload, req);
205 if (ret)
206 goto failjob_rls_job;
207 }
208 if (rsp && rsp->bio) {
209 ret = bsg_map_buffer(&job->reply_payload, rsp);
210 if (ret)
211 goto failjob_rls_rqst_payload;
212 }
213 job->dev = dev;
214 /* take a reference for the request */
215 get_device(job->dev);
bf0f2d38 216 kref_init(&job->kref);
17cb960f 217 return true;
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MC
218
219failjob_rls_rqst_payload:
220 kfree(job->request_payload.sg_list);
221failjob_rls_job:
17cb960f
CH
222 job->result = -ENOMEM;
223 return false;
aa387cc8
MC
224}
225
aa387cc8
MC
226/**
227 * bsg_request_fn - generic handler for bsg requests
228 * @q: request queue to manage
229 *
230 * On error the create_bsg_job function should return a -Exyz error value
17d5363b 231 * that will be set to ->result.
aa387cc8
MC
232 *
233 * Drivers/subsys should pass this to the queue init function.
234 */
8ae94eb6 235static void bsg_request_fn(struct request_queue *q)
dbb3ab03
BVA
236 __releases(q->queue_lock)
237 __acquires(q->queue_lock)
aa387cc8
MC
238{
239 struct device *dev = q->queuedata;
240 struct request *req;
aa387cc8
MC
241 int ret;
242
243 if (!get_device(dev))
244 return;
245
246 while (1) {
247 req = blk_fetch_request(q);
248 if (!req)
249 break;
250 spin_unlock_irq(q->queue_lock);
251
17cb960f 252 if (!bsg_prepare_job(dev, req)) {
2a842aca 253 blk_end_request_all(req, BLK_STS_OK);
aa387cc8
MC
254 spin_lock_irq(q->queue_lock);
255 continue;
256 }
257
50b4d485 258 ret = q->bsg_job_fn(blk_mq_rq_to_pdu(req));
aa387cc8
MC
259 spin_lock_irq(q->queue_lock);
260 if (ret)
261 break;
262 }
263
264 spin_unlock_irq(q->queue_lock);
265 put_device(dev);
266 spin_lock_irq(q->queue_lock);
267}
aa387cc8 268
17cb960f 269/* called right after the request is allocated for the request_queue */
50b4d485
BB
270static int bsg_init_rq(struct request_queue *q, struct request *req, gfp_t gfp)
271{
272 struct bsg_job *job = blk_mq_rq_to_pdu(req);
eab40cf3 273
17cb960f
CH
274 job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, gfp);
275 if (!job->reply)
eab40cf3 276 return -ENOMEM;
eab40cf3
BB
277 return 0;
278}
279
17cb960f 280/* called right before the request is given to the request_queue user */
eab40cf3
BB
281static void bsg_initialize_rq(struct request *req)
282{
283 struct bsg_job *job = blk_mq_rq_to_pdu(req);
17cb960f 284 void *reply = job->reply;
eab40cf3 285
50b4d485 286 memset(job, 0, sizeof(*job));
17cb960f
CH
287 job->reply = reply;
288 job->reply_len = SCSI_SENSE_BUFFERSIZE;
50b4d485 289 job->dd_data = job + 1;
50b4d485
BB
290}
291
292static void bsg_exit_rq(struct request_queue *q, struct request *req)
293{
294 struct bsg_job *job = blk_mq_rq_to_pdu(req);
50b4d485 295
17cb960f 296 kfree(job->reply);
50b4d485
BB
297}
298
aa387cc8
MC
299/**
300 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
301 * @dev: device to attach bsg device to
aa387cc8
MC
302 * @name: device to give bsg device
303 * @job_fn: bsg job handler
304 * @dd_job_size: size of LLD data needed for each job
aa387cc8 305 */
c1225f01 306struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
5de815a7 307 bsg_job_fn *job_fn, int dd_job_size)
aa387cc8 308{
8ae94eb6 309 struct request_queue *q;
aa387cc8
MC
310 int ret;
311
82ed4db4 312 q = blk_alloc_queue(GFP_KERNEL);
8ae94eb6
CH
313 if (!q)
314 return ERR_PTR(-ENOMEM);
50b4d485
BB
315 q->cmd_size = sizeof(struct bsg_job) + dd_job_size;
316 q->init_rq_fn = bsg_init_rq;
317 q->exit_rq_fn = bsg_exit_rq;
eab40cf3 318 q->initialize_rq_fn = bsg_initialize_rq;
82ed4db4
CH
319 q->request_fn = bsg_request_fn;
320
321 ret = blk_init_allocated_queue(q);
322 if (ret)
323 goto out_cleanup_queue;
8ae94eb6 324
aa387cc8 325 q->queuedata = dev;
aa387cc8 326 q->bsg_job_fn = job_fn;
8b904b5b 327 blk_queue_flag_set(QUEUE_FLAG_BIDI, q);
aa387cc8
MC
328 blk_queue_softirq_done(q, bsg_softirq_done);
329 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
330
5de815a7 331 ret = bsg_register_queue(q, dev, name, &bsg_transport_ops);
aa387cc8
MC
332 if (ret) {
333 printk(KERN_ERR "%s: bsg interface failed to "
334 "initialize - register queue\n", dev->kobj.name);
82ed4db4 335 goto out_cleanup_queue;
aa387cc8
MC
336 }
337
8ae94eb6 338 return q;
82ed4db4
CH
339out_cleanup_queue:
340 blk_cleanup_queue(q);
341 return ERR_PTR(ret);
aa387cc8
MC
342}
343EXPORT_SYMBOL_GPL(bsg_setup_queue);