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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// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * BSG helper library
4 *
5 * Copyright (C) 2008 James Smart, Emulex Corporation
6 * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
7 * Copyright (C) 2011 Mike Christie
8 */
9#include <linux/slab.h>
10#include <linux/blk-mq.h>
11#include <linux/delay.h>
12#include <linux/scatterlist.h>
13#include <linux/bsg-lib.h>
14#include <linux/export.h>
15#include <scsi/scsi_cmnd.h>
16#include <scsi/sg.h>
17
18#define uptr64(val) ((void __user *)(uintptr_t)(val))
19
20struct bsg_set {
21 struct blk_mq_tag_set tag_set;
22 bsg_job_fn *job_fn;
23 bsg_timeout_fn *timeout_fn;
24};
25
26static int bsg_transport_check_proto(struct sg_io_v4 *hdr)
27{
28 if (hdr->protocol != BSG_PROTOCOL_SCSI ||
29 hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_TRANSPORT)
30 return -EINVAL;
31 if (!capable(CAP_SYS_RAWIO))
32 return -EPERM;
33 return 0;
34}
35
36static int bsg_transport_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
37 fmode_t mode)
38{
39 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
40 int ret;
41
42 job->request_len = hdr->request_len;
43 job->request = memdup_user(uptr64(hdr->request), hdr->request_len);
44 if (IS_ERR(job->request))
45 return PTR_ERR(job->request);
46
47 if (hdr->dout_xfer_len && hdr->din_xfer_len) {
48 job->bidi_rq = blk_get_request(rq->q, REQ_OP_SCSI_IN, 0);
49 if (IS_ERR(job->bidi_rq)) {
50 ret = PTR_ERR(job->bidi_rq);
51 goto out;
52 }
53
54 ret = blk_rq_map_user(rq->q, job->bidi_rq, NULL,
55 uptr64(hdr->din_xferp), hdr->din_xfer_len,
56 GFP_KERNEL);
57 if (ret)
58 goto out_free_bidi_rq;
59
60 job->bidi_bio = job->bidi_rq->bio;
61 } else {
62 job->bidi_rq = NULL;
63 job->bidi_bio = NULL;
64 }
65
66 return 0;
67
68out_free_bidi_rq:
69 if (job->bidi_rq)
70 blk_put_request(job->bidi_rq);
71out:
72 kfree(job->request);
73 return ret;
74}
75
76static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
77{
78 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
79 int ret = 0;
80
81 /*
82 * The assignments below don't make much sense, but are kept for
83 * bug by bug backwards compatibility:
84 */
85 hdr->device_status = job->result & 0xff;
86 hdr->transport_status = host_byte(job->result);
87 hdr->driver_status = driver_byte(job->result);
88 hdr->info = 0;
89 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
90 hdr->info |= SG_INFO_CHECK;
91 hdr->response_len = 0;
92
93 if (job->result < 0) {
94 /* we're only returning the result field in the reply */
95 job->reply_len = sizeof(u32);
96 ret = job->result;
97 }
98
99 if (job->reply_len && hdr->response) {
100 int len = min(hdr->max_response_len, job->reply_len);
101
102 if (copy_to_user(uptr64(hdr->response), job->reply, len))
103 ret = -EFAULT;
104 else
105 hdr->response_len = len;
106 }
107
108 /* we assume all request payload was transferred, residual == 0 */
109 hdr->dout_resid = 0;
110
111 if (job->bidi_rq) {
112 unsigned int rsp_len = job->reply_payload.payload_len;
113
114 if (WARN_ON(job->reply_payload_rcv_len > rsp_len))
115 hdr->din_resid = 0;
116 else
117 hdr->din_resid = rsp_len - job->reply_payload_rcv_len;
118 } else {
119 hdr->din_resid = 0;
120 }
121
122 return ret;
123}
124
125static void bsg_transport_free_rq(struct request *rq)
126{
127 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
128
129 if (job->bidi_rq) {
130 blk_rq_unmap_user(job->bidi_bio);
131 blk_put_request(job->bidi_rq);
132 }
133
134 kfree(job->request);
135}
136
137static const struct bsg_ops bsg_transport_ops = {
138 .check_proto = bsg_transport_check_proto,
139 .fill_hdr = bsg_transport_fill_hdr,
140 .complete_rq = bsg_transport_complete_rq,
141 .free_rq = bsg_transport_free_rq,
142};
143
144/**
145 * bsg_teardown_job - routine to teardown a bsg job
146 * @kref: kref inside bsg_job that is to be torn down
147 */
148static void bsg_teardown_job(struct kref *kref)
149{
150 struct bsg_job *job = container_of(kref, struct bsg_job, kref);
151 struct request *rq = blk_mq_rq_from_pdu(job);
152
153 put_device(job->dev); /* release reference for the request */
154
155 kfree(job->request_payload.sg_list);
156 kfree(job->reply_payload.sg_list);
157
158 blk_mq_end_request(rq, BLK_STS_OK);
159}
160
161void bsg_job_put(struct bsg_job *job)
162{
163 kref_put(&job->kref, bsg_teardown_job);
164}
165EXPORT_SYMBOL_GPL(bsg_job_put);
166
167int bsg_job_get(struct bsg_job *job)
168{
169 return kref_get_unless_zero(&job->kref);
170}
171EXPORT_SYMBOL_GPL(bsg_job_get);
172
173/**
174 * bsg_job_done - completion routine for bsg requests
175 * @job: bsg_job that is complete
176 * @result: job reply result
177 * @reply_payload_rcv_len: length of payload recvd
178 *
179 * The LLD should call this when the bsg job has completed.
180 */
181void bsg_job_done(struct bsg_job *job, int result,
182 unsigned int reply_payload_rcv_len)
183{
184 struct request *rq = blk_mq_rq_from_pdu(job);
185
186 job->result = result;
187 job->reply_payload_rcv_len = reply_payload_rcv_len;
188 if (likely(!blk_should_fake_timeout(rq->q)))
189 blk_mq_complete_request(rq);
190}
191EXPORT_SYMBOL_GPL(bsg_job_done);
192
193/**
194 * bsg_complete - softirq done routine for destroying the bsg requests
195 * @rq: BSG request that holds the job to be destroyed
196 */
197static void bsg_complete(struct request *rq)
198{
199 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
200
201 bsg_job_put(job);
202}
203
204static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
205{
206 size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
207
208 BUG_ON(!req->nr_phys_segments);
209
210 buf->sg_list = kzalloc(sz, GFP_KERNEL);
211 if (!buf->sg_list)
212 return -ENOMEM;
213 sg_init_table(buf->sg_list, req->nr_phys_segments);
214 buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
215 buf->payload_len = blk_rq_bytes(req);
216 return 0;
217}
218
219/**
220 * bsg_prepare_job - create the bsg_job structure for the bsg request
221 * @dev: device that is being sent the bsg request
222 * @req: BSG request that needs a job structure
223 */
224static bool bsg_prepare_job(struct device *dev, struct request *req)
225{
226 struct bsg_job *job = blk_mq_rq_to_pdu(req);
227 int ret;
228
229 job->timeout = req->timeout;
230
231 if (req->bio) {
232 ret = bsg_map_buffer(&job->request_payload, req);
233 if (ret)
234 goto failjob_rls_job;
235 }
236 if (job->bidi_rq) {
237 ret = bsg_map_buffer(&job->reply_payload, job->bidi_rq);
238 if (ret)
239 goto failjob_rls_rqst_payload;
240 }
241 job->dev = dev;
242 /* take a reference for the request */
243 get_device(job->dev);
244 kref_init(&job->kref);
245 return true;
246
247failjob_rls_rqst_payload:
248 kfree(job->request_payload.sg_list);
249failjob_rls_job:
250 job->result = -ENOMEM;
251 return false;
252}
253
254/**
255 * bsg_queue_rq - generic handler for bsg requests
256 * @hctx: hardware queue
257 * @bd: queue data
258 *
259 * On error the create_bsg_job function should return a -Exyz error value
260 * that will be set to ->result.
261 *
262 * Drivers/subsys should pass this to the queue init function.
263 */
264static blk_status_t bsg_queue_rq(struct blk_mq_hw_ctx *hctx,
265 const struct blk_mq_queue_data *bd)
266{
267 struct request_queue *q = hctx->queue;
268 struct device *dev = q->queuedata;
269 struct request *req = bd->rq;
270 struct bsg_set *bset =
271 container_of(q->tag_set, struct bsg_set, tag_set);
272 blk_status_t sts = BLK_STS_IOERR;
273 int ret;
274
275 blk_mq_start_request(req);
276
277 if (!get_device(dev))
278 return BLK_STS_IOERR;
279
280 if (!bsg_prepare_job(dev, req))
281 goto out;
282
283 ret = bset->job_fn(blk_mq_rq_to_pdu(req));
284 if (!ret)
285 sts = BLK_STS_OK;
286
287out:
288 put_device(dev);
289 return sts;
290}
291
292/* called right after the request is allocated for the request_queue */
293static int bsg_init_rq(struct blk_mq_tag_set *set, struct request *req,
294 unsigned int hctx_idx, unsigned int numa_node)
295{
296 struct bsg_job *job = blk_mq_rq_to_pdu(req);
297
298 job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL);
299 if (!job->reply)
300 return -ENOMEM;
301 return 0;
302}
303
304/* called right before the request is given to the request_queue user */
305static void bsg_initialize_rq(struct request *req)
306{
307 struct bsg_job *job = blk_mq_rq_to_pdu(req);
308 void *reply = job->reply;
309
310 memset(job, 0, sizeof(*job));
311 job->reply = reply;
312 job->reply_len = SCSI_SENSE_BUFFERSIZE;
313 job->dd_data = job + 1;
314}
315
316static void bsg_exit_rq(struct blk_mq_tag_set *set, struct request *req,
317 unsigned int hctx_idx)
318{
319 struct bsg_job *job = blk_mq_rq_to_pdu(req);
320
321 kfree(job->reply);
322}
323
324void bsg_remove_queue(struct request_queue *q)
325{
326 if (q) {
327 struct bsg_set *bset =
328 container_of(q->tag_set, struct bsg_set, tag_set);
329
330 bsg_unregister_queue(q);
331 blk_cleanup_queue(q);
332 blk_mq_free_tag_set(&bset->tag_set);
333 kfree(bset);
334 }
335}
336EXPORT_SYMBOL_GPL(bsg_remove_queue);
337
338static enum blk_eh_timer_return bsg_timeout(struct request *rq, bool reserved)
339{
340 struct bsg_set *bset =
341 container_of(rq->q->tag_set, struct bsg_set, tag_set);
342
343 if (!bset->timeout_fn)
344 return BLK_EH_DONE;
345 return bset->timeout_fn(rq);
346}
347
348static const struct blk_mq_ops bsg_mq_ops = {
349 .queue_rq = bsg_queue_rq,
350 .init_request = bsg_init_rq,
351 .exit_request = bsg_exit_rq,
352 .initialize_rq_fn = bsg_initialize_rq,
353 .complete = bsg_complete,
354 .timeout = bsg_timeout,
355};
356
357/**
358 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
359 * @dev: device to attach bsg device to
360 * @name: device to give bsg device
361 * @job_fn: bsg job handler
362 * @timeout: timeout handler function pointer
363 * @dd_job_size: size of LLD data needed for each job
364 */
365struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
366 bsg_job_fn *job_fn, bsg_timeout_fn *timeout, int dd_job_size)
367{
368 struct bsg_set *bset;
369 struct blk_mq_tag_set *set;
370 struct request_queue *q;
371 int ret = -ENOMEM;
372
373 bset = kzalloc(sizeof(*bset), GFP_KERNEL);
374 if (!bset)
375 return ERR_PTR(-ENOMEM);
376
377 bset->job_fn = job_fn;
378 bset->timeout_fn = timeout;
379
380 set = &bset->tag_set;
381 set->ops = &bsg_mq_ops;
382 set->nr_hw_queues = 1;
383 set->queue_depth = 128;
384 set->numa_node = NUMA_NO_NODE;
385 set->cmd_size = sizeof(struct bsg_job) + dd_job_size;
386 set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING;
387 if (blk_mq_alloc_tag_set(set))
388 goto out_tag_set;
389
390 q = blk_mq_init_queue(set);
391 if (IS_ERR(q)) {
392 ret = PTR_ERR(q);
393 goto out_queue;
394 }
395
396 q->queuedata = dev;
397 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
398
399 ret = bsg_register_queue(q, dev, name, &bsg_transport_ops);
400 if (ret) {
401 printk(KERN_ERR "%s: bsg interface failed to "
402 "initialize - register queue\n", dev->kobj.name);
403 goto out_cleanup_queue;
404 }
405
406 return q;
407out_cleanup_queue:
408 blk_cleanup_queue(q);
409out_queue:
410 blk_mq_free_tag_set(set);
411out_tag_set:
412 kfree(bset);
413 return ERR_PTR(ret);
414}
415EXPORT_SYMBOL_GPL(bsg_setup_queue);