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, opf: hdr->dout_xfer_len ? |
44 | REQ_OP_DRV_OUT : REQ_OP_DRV_IN, flags: 0); |
45 | if (IS_ERR(ptr: rq)) |
46 | return PTR_ERR(ptr: 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(ptr: job->request)) { |
59 | ret = PTR_ERR(ptr: 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(q: rq->q, opf: REQ_OP_DRV_IN, flags: 0); |
65 | if (IS_ERR(ptr: job->bidi_rq)) { |
66 | ret = PTR_ERR(ptr: 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, at_head: !(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), from: job->reply, n: 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(rq: job->bidi_rq); |
145 | out_free_job_request: |
146 | kfree(objp: 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(pdu: job); |
160 | |
161 | put_device(dev: job->dev); /* release reference for the request */ |
162 | |
163 | kfree(objp: job->request_payload.sg_list); |
164 | kfree(objp: 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(kref: &job->kref, release: 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(kref: &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(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(size: 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(q: req->q, rq: req, sglist: buf->sg_list); |
223 | buf->payload_len = blk_rq_bytes(rq: 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(rq: req); |
235 | int ret; |
236 | |
237 | job->timeout = req->timeout; |
238 | |
239 | if (req->bio) { |
240 | ret = bsg_map_buffer(buf: &job->request_payload, req); |
241 | if (ret) |
242 | goto failjob_rls_job; |
243 | } |
244 | if (job->bidi_rq) { |
245 | ret = bsg_map_buffer(buf: &job->reply_payload, req: 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(dev: job->dev); |
252 | kref_init(kref: &job->kref); |
253 | return true; |
254 | |
255 | failjob_rls_rqst_payload: |
256 | kfree(objp: 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(rq: 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(rq: 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(rq: 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(rq: req); |
316 | |
317 | kfree(objp: 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(bcd: bset->bd); |
327 | blk_mq_destroy_queue(q); |
328 | blk_put_queue(q); |
329 | blk_mq_free_tag_set(set: &bset->tag_set); |
330 | kfree(objp: 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 | * @job_fn: bsg job handler |
358 | * @timeout: timeout handler function pointer |
359 | * @dd_job_size: size of LLD data needed for each job |
360 | */ |
361 | struct request_queue *bsg_setup_queue(struct device *dev, const char *name, |
362 | bsg_job_fn *job_fn, bsg_timeout_fn *timeout, int dd_job_size) |
363 | { |
364 | struct bsg_set *bset; |
365 | struct blk_mq_tag_set *set; |
366 | struct request_queue *q; |
367 | int ret = -ENOMEM; |
368 | |
369 | bset = kzalloc(size: sizeof(*bset), GFP_KERNEL); |
370 | if (!bset) |
371 | return ERR_PTR(error: -ENOMEM); |
372 | |
373 | bset->job_fn = job_fn; |
374 | bset->timeout_fn = timeout; |
375 | |
376 | set = &bset->tag_set; |
377 | set->ops = &bsg_mq_ops; |
378 | set->nr_hw_queues = 1; |
379 | set->queue_depth = 128; |
380 | set->numa_node = NUMA_NO_NODE; |
381 | set->cmd_size = sizeof(struct bsg_job) + dd_job_size; |
382 | set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING; |
383 | if (blk_mq_alloc_tag_set(set)) |
384 | goto out_tag_set; |
385 | |
386 | q = blk_mq_init_queue(set); |
387 | if (IS_ERR(ptr: q)) { |
388 | ret = PTR_ERR(ptr: q); |
389 | goto out_queue; |
390 | } |
391 | |
392 | q->queuedata = dev; |
393 | blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); |
394 | |
395 | bset->bd = bsg_register_queue(q, parent: dev, name, sg_io_fn: bsg_transport_sg_io_fn); |
396 | if (IS_ERR(ptr: bset->bd)) { |
397 | ret = PTR_ERR(ptr: bset->bd); |
398 | goto out_cleanup_queue; |
399 | } |
400 | |
401 | return q; |
402 | out_cleanup_queue: |
403 | blk_mq_destroy_queue(q); |
404 | blk_put_queue(q); |
405 | out_queue: |
406 | blk_mq_free_tag_set(set); |
407 | out_tag_set: |
408 | kfree(objp: bset); |
409 | return ERR_PTR(error: ret); |
410 | } |
411 | EXPORT_SYMBOL_GPL(bsg_setup_queue); |
412 | |