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
20 struct bsg_set {
21 struct blk_mq_tag_set tag_set;
22 bsg_job_fn *job_fn;
23 bsg_timeout_fn *timeout_fn;
24 };
25
bsg_transport_check_proto(struct sg_io_v4 * hdr)26 static 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
bsg_transport_fill_hdr(struct request * rq,struct sg_io_v4 * hdr,fmode_t mode)36 static 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
68 out_free_bidi_rq:
69 if (job->bidi_rq)
70 blk_put_request(job->bidi_rq);
71 out:
72 kfree(job->request);
73 return ret;
74 }
75
bsg_transport_complete_rq(struct request * rq,struct sg_io_v4 * hdr)76 static 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
bsg_transport_free_rq(struct request * rq)125 static 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
137 static 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 */
bsg_teardown_job(struct kref * kref)148 static 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
bsg_job_put(struct bsg_job * job)161 void bsg_job_put(struct bsg_job *job)
162 {
163 kref_put(&job->kref, bsg_teardown_job);
164 }
165 EXPORT_SYMBOL_GPL(bsg_job_put);
166
bsg_job_get(struct bsg_job * job)167 int bsg_job_get(struct bsg_job *job)
168 {
169 return kref_get_unless_zero(&job->kref);
170 }
171 EXPORT_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 */
bsg_job_done(struct bsg_job * job,int result,unsigned int reply_payload_rcv_len)181 void 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 }
191 EXPORT_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 */
bsg_complete(struct request * rq)197 static 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
bsg_map_buffer(struct bsg_buffer * buf,struct request * req)204 static 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 = kmalloc(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 */
bsg_prepare_job(struct device * dev,struct request * req)224 static 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
247 failjob_rls_rqst_payload:
248 kfree(job->request_payload.sg_list);
249 failjob_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 */
bsg_queue_rq(struct blk_mq_hw_ctx * hctx,const struct blk_mq_queue_data * bd)264 static 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
287 out:
288 put_device(dev);
289 return sts;
290 }
291
292 /* 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)293 static 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 */
bsg_initialize_rq(struct request * req)305 static 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
bsg_exit_rq(struct blk_mq_tag_set * set,struct request * req,unsigned int hctx_idx)316 static 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
bsg_remove_queue(struct request_queue * q)324 void 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 }
336 EXPORT_SYMBOL_GPL(bsg_remove_queue);
337
bsg_timeout(struct request * rq,bool reserved)338 static 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
348 static 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 */
bsg_setup_queue(struct device * dev,const char * name,bsg_job_fn * job_fn,bsg_timeout_fn * timeout,int dd_job_size)365 struct 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;
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
