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/bsg.h>
10 #include <linux/slab.h>
11 #include <linux/blk-mq.h>
12 #include <linux/delay.h>
13 #include <linux/scatterlist.h>
14 #include <linux/bsg-lib.h>
15 #include <linux/export.h>
16 #include <scsi/scsi_cmnd.h>
17 #include <scsi/sg.h>
18
19 #define uptr64(val) ((void __user *)(uintptr_t)(val))
20
21 struct bsg_set {
22 struct blk_mq_tag_set tag_set;
23 struct bsg_device *bd;
24 bsg_job_fn *job_fn;
25 bsg_timeout_fn *timeout_fn;
26 };
27
bsg_transport_sg_io_fn(struct request_queue * q,struct sg_io_v4 * hdr,fmode_t mode,unsigned int timeout)28 static int bsg_transport_sg_io_fn(struct request_queue *q, struct sg_io_v4 *hdr,
29 fmode_t mode, unsigned int timeout)
30 {
31 struct bsg_job *job;
32 struct request *rq;
33 struct bio *bio;
34 int ret;
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
42 rq = blk_get_request(q, hdr->dout_xfer_len ?
43 REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
44 if (IS_ERR(rq))
45 return PTR_ERR(rq);
46 rq->timeout = timeout;
47
48 job = blk_mq_rq_to_pdu(rq);
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 ret = PTR_ERR(job->request);
53 goto out_put_request;
54 }
55
56 if (hdr->dout_xfer_len && hdr->din_xfer_len) {
57 job->bidi_rq = blk_get_request(rq->q, REQ_OP_DRV_IN, 0);
58 if (IS_ERR(job->bidi_rq)) {
59 ret = PTR_ERR(job->bidi_rq);
60 goto out_free_job_request;
61 }
62
63 ret = blk_rq_map_user(rq->q, job->bidi_rq, NULL,
64 uptr64(hdr->din_xferp), hdr->din_xfer_len,
65 GFP_KERNEL);
66 if (ret)
67 goto out_free_bidi_rq;
68
69 job->bidi_bio = job->bidi_rq->bio;
70 } else {
71 job->bidi_rq = NULL;
72 job->bidi_bio = NULL;
73 }
74
75 ret = 0;
76 if (hdr->dout_xfer_len) {
77 ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->dout_xferp),
78 hdr->dout_xfer_len, GFP_KERNEL);
79 } else if (hdr->din_xfer_len) {
80 ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->din_xferp),
81 hdr->din_xfer_len, GFP_KERNEL);
82 }
83
84 if (ret)
85 goto out_unmap_bidi_rq;
86
87 bio = rq->bio;
88 blk_execute_rq(NULL, rq, !(hdr->flags & BSG_FLAG_Q_AT_TAIL));
89
90 /*
91 * The assignments below don't make much sense, but are kept for
92 * bug by bug backwards compatibility:
93 */
94 hdr->device_status = job->result & 0xff;
95 hdr->transport_status = host_byte(job->result);
96 hdr->driver_status = 0;
97 hdr->info = 0;
98 if (hdr->device_status || hdr->transport_status || hdr->driver_status)
99 hdr->info |= SG_INFO_CHECK;
100 hdr->response_len = 0;
101
102 if (job->result < 0) {
103 /* we're only returning the result field in the reply */
104 job->reply_len = sizeof(u32);
105 ret = job->result;
106 }
107
108 if (job->reply_len && hdr->response) {
109 int len = min(hdr->max_response_len, job->reply_len);
110
111 if (copy_to_user(uptr64(hdr->response), job->reply, len))
112 ret = -EFAULT;
113 else
114 hdr->response_len = len;
115 }
116
117 /* we assume all request payload was transferred, residual == 0 */
118 hdr->dout_resid = 0;
119
120 if (job->bidi_rq) {
121 unsigned int rsp_len = job->reply_payload.payload_len;
122
123 if (WARN_ON(job->reply_payload_rcv_len > rsp_len))
124 hdr->din_resid = 0;
125 else
126 hdr->din_resid = rsp_len - job->reply_payload_rcv_len;
127 } else {
128 hdr->din_resid = 0;
129 }
130
131 blk_rq_unmap_user(bio);
132 out_unmap_bidi_rq:
133 if (job->bidi_rq)
134 blk_rq_unmap_user(job->bidi_bio);
135 out_free_bidi_rq:
136 if (job->bidi_rq)
137 blk_put_request(job->bidi_rq);
138 out_free_job_request:
139 kfree(job->request);
140 out_put_request:
141 blk_put_request(rq);
142 return ret;
143 }
144
145 /**
146 * bsg_teardown_job - routine to teardown a bsg job
147 * @kref: kref inside bsg_job that is to be torn down
148 */
bsg_teardown_job(struct kref * kref)149 static void bsg_teardown_job(struct kref *kref)
150 {
151 struct bsg_job *job = container_of(kref, struct bsg_job, kref);
152 struct request *rq = blk_mq_rq_from_pdu(job);
153
154 put_device(job->dev); /* release reference for the request */
155
156 kfree(job->request_payload.sg_list);
157 kfree(job->reply_payload.sg_list);
158
159 blk_mq_end_request(rq, BLK_STS_OK);
160 }
161
bsg_job_put(struct bsg_job * job)162 void bsg_job_put(struct bsg_job *job)
163 {
164 kref_put(&job->kref, bsg_teardown_job);
165 }
166 EXPORT_SYMBOL_GPL(bsg_job_put);
167
bsg_job_get(struct bsg_job * job)168 int bsg_job_get(struct bsg_job *job)
169 {
170 return kref_get_unless_zero(&job->kref);
171 }
172 EXPORT_SYMBOL_GPL(bsg_job_get);
173
174 /**
175 * bsg_job_done - completion routine for bsg requests
176 * @job: bsg_job that is complete
177 * @result: job reply result
178 * @reply_payload_rcv_len: length of payload recvd
179 *
180 * The LLD should call this when the bsg job has completed.
181 */
bsg_job_done(struct bsg_job * job,int result,unsigned int reply_payload_rcv_len)182 void bsg_job_done(struct bsg_job *job, int result,
183 unsigned int reply_payload_rcv_len)
184 {
185 struct request *rq = blk_mq_rq_from_pdu(job);
186
187 job->result = result;
188 job->reply_payload_rcv_len = reply_payload_rcv_len;
189 if (likely(!blk_should_fake_timeout(rq->q)))
190 blk_mq_complete_request(rq);
191 }
192 EXPORT_SYMBOL_GPL(bsg_job_done);
193
194 /**
195 * bsg_complete - softirq done routine for destroying the bsg requests
196 * @rq: BSG request that holds the job to be destroyed
197 */
bsg_complete(struct request * rq)198 static void bsg_complete(struct request *rq)
199 {
200 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
201
202 bsg_job_put(job);
203 }
204
bsg_map_buffer(struct bsg_buffer * buf,struct request * req)205 static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
206 {
207 size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
208
209 BUG_ON(!req->nr_phys_segments);
210
211 buf->sg_list = kmalloc(sz, GFP_KERNEL);
212 if (!buf->sg_list)
213 return -ENOMEM;
214 sg_init_table(buf->sg_list, req->nr_phys_segments);
215 buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
216 buf->payload_len = blk_rq_bytes(req);
217 return 0;
218 }
219
220 /**
221 * bsg_prepare_job - create the bsg_job structure for the bsg request
222 * @dev: device that is being sent the bsg request
223 * @req: BSG request that needs a job structure
224 */
bsg_prepare_job(struct device * dev,struct request * req)225 static bool bsg_prepare_job(struct device *dev, struct request *req)
226 {
227 struct bsg_job *job = blk_mq_rq_to_pdu(req);
228 int ret;
229
230 job->timeout = req->timeout;
231
232 if (req->bio) {
233 ret = bsg_map_buffer(&job->request_payload, req);
234 if (ret)
235 goto failjob_rls_job;
236 }
237 if (job->bidi_rq) {
238 ret = bsg_map_buffer(&job->reply_payload, job->bidi_rq);
239 if (ret)
240 goto failjob_rls_rqst_payload;
241 }
242 job->dev = dev;
243 /* take a reference for the request */
244 get_device(job->dev);
245 kref_init(&job->kref);
246 return true;
247
248 failjob_rls_rqst_payload:
249 kfree(job->request_payload.sg_list);
250 failjob_rls_job:
251 job->result = -ENOMEM;
252 return false;
253 }
254
255 /**
256 * bsg_queue_rq - generic handler for bsg requests
257 * @hctx: hardware queue
258 * @bd: queue data
259 *
260 * On error the create_bsg_job function should return a -Exyz error value
261 * that will be set to ->result.
262 *
263 * Drivers/subsys should pass this to the queue init function.
264 */
bsg_queue_rq(struct blk_mq_hw_ctx * hctx,const struct blk_mq_queue_data * bd)265 static blk_status_t bsg_queue_rq(struct blk_mq_hw_ctx *hctx,
266 const struct blk_mq_queue_data *bd)
267 {
268 struct request_queue *q = hctx->queue;
269 struct device *dev = q->queuedata;
270 struct request *req = bd->rq;
271 struct bsg_set *bset =
272 container_of(q->tag_set, struct bsg_set, tag_set);
273 blk_status_t sts = BLK_STS_IOERR;
274 int ret;
275
276 blk_mq_start_request(req);
277
278 if (!get_device(dev))
279 return BLK_STS_IOERR;
280
281 if (!bsg_prepare_job(dev, req))
282 goto out;
283
284 ret = bset->job_fn(blk_mq_rq_to_pdu(req));
285 if (!ret)
286 sts = BLK_STS_OK;
287
288 out:
289 put_device(dev);
290 return sts;
291 }
292
293 /* called right after the request is allocated for the request_queue */
bsg_init_rq(struct blk_mq_tag_set * set,struct request * req,unsigned int hctx_idx,unsigned int numa_node)294 static int bsg_init_rq(struct blk_mq_tag_set *set, struct request *req,
295 unsigned int hctx_idx, unsigned int numa_node)
296 {
297 struct bsg_job *job = blk_mq_rq_to_pdu(req);
298
299 job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL);
300 if (!job->reply)
301 return -ENOMEM;
302 return 0;
303 }
304
305 /* called right before the request is given to the request_queue user */
bsg_initialize_rq(struct request * req)306 static void bsg_initialize_rq(struct request *req)
307 {
308 struct bsg_job *job = blk_mq_rq_to_pdu(req);
309 void *reply = job->reply;
310
311 memset(job, 0, sizeof(*job));
312 job->reply = reply;
313 job->reply_len = SCSI_SENSE_BUFFERSIZE;
314 job->dd_data = job + 1;
315 }
316
bsg_exit_rq(struct blk_mq_tag_set * set,struct request * req,unsigned int hctx_idx)317 static void bsg_exit_rq(struct blk_mq_tag_set *set, struct request *req,
318 unsigned int hctx_idx)
319 {
320 struct bsg_job *job = blk_mq_rq_to_pdu(req);
321
322 kfree(job->reply);
323 }
324
bsg_remove_queue(struct request_queue * q)325 void bsg_remove_queue(struct request_queue *q)
326 {
327 if (q) {
328 struct bsg_set *bset =
329 container_of(q->tag_set, struct bsg_set, tag_set);
330
331 bsg_unregister_queue(bset->bd);
332 blk_cleanup_queue(q);
333 blk_mq_free_tag_set(&bset->tag_set);
334 kfree(bset);
335 }
336 }
337 EXPORT_SYMBOL_GPL(bsg_remove_queue);
338
bsg_timeout(struct request * rq,bool reserved)339 static enum blk_eh_timer_return bsg_timeout(struct request *rq, bool reserved)
340 {
341 struct bsg_set *bset =
342 container_of(rq->q->tag_set, struct bsg_set, tag_set);
343
344 if (!bset->timeout_fn)
345 return BLK_EH_DONE;
346 return bset->timeout_fn(rq);
347 }
348
349 static const struct blk_mq_ops bsg_mq_ops = {
350 .queue_rq = bsg_queue_rq,
351 .init_request = bsg_init_rq,
352 .exit_request = bsg_exit_rq,
353 .initialize_rq_fn = bsg_initialize_rq,
354 .complete = bsg_complete,
355 .timeout = bsg_timeout,
356 };
357
358 /**
359 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
360 * @dev: device to attach bsg device to
361 * @name: device to give bsg device
362 * @job_fn: bsg job handler
363 * @timeout: timeout handler function pointer
364 * @dd_job_size: size of LLD data needed for each job
365 */
bsg_setup_queue(struct device * dev,const char * name,bsg_job_fn * job_fn,bsg_timeout_fn * timeout,int dd_job_size)366 struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
367 bsg_job_fn *job_fn, bsg_timeout_fn *timeout, int dd_job_size)
368 {
369 struct bsg_set *bset;
370 struct blk_mq_tag_set *set;
371 struct request_queue *q;
372 int ret = -ENOMEM;
373
374 bset = kzalloc(sizeof(*bset), GFP_KERNEL);
375 if (!bset)
376 return ERR_PTR(-ENOMEM);
377
378 bset->job_fn = job_fn;
379 bset->timeout_fn = timeout;
380
381 set = &bset->tag_set;
382 set->ops = &bsg_mq_ops;
383 set->nr_hw_queues = 1;
384 set->queue_depth = 128;
385 set->numa_node = NUMA_NO_NODE;
386 set->cmd_size = sizeof(struct bsg_job) + dd_job_size;
387 set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING;
388 if (blk_mq_alloc_tag_set(set))
389 goto out_tag_set;
390
391 q = blk_mq_init_queue(set);
392 if (IS_ERR(q)) {
393 ret = PTR_ERR(q);
394 goto out_queue;
395 }
396
397 q->queuedata = dev;
398 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
399
400 bset->bd = bsg_register_queue(q, dev, name, bsg_transport_sg_io_fn);
401 if (IS_ERR(bset->bd)) {
402 ret = PTR_ERR(bset->bd);
403 goto out_cleanup_queue;
404 }
405
406 return q;
407 out_cleanup_queue:
408 blk_cleanup_queue(q);
409 out_queue:
410 blk_mq_free_tag_set(set);
411 out_tag_set:
412 kfree(bset);
413 return ERR_PTR(ret);
414 }
415 EXPORT_SYMBOL_GPL(bsg_setup_queue);
416