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