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 job->result = result;
185 job->reply_payload_rcv_len = reply_payload_rcv_len;
186 blk_mq_complete_request(blk_mq_rq_from_pdu(job));
187 }
188 EXPORT_SYMBOL_GPL(bsg_job_done);
189
190 /**
191 * bsg_complete - softirq done routine for destroying the bsg requests
192 * @rq: BSG request that holds the job to be destroyed
193 */
bsg_complete(struct request * rq)194 static void bsg_complete(struct request *rq)
195 {
196 struct bsg_job *job = blk_mq_rq_to_pdu(rq);
197
198 bsg_job_put(job);
199 }
200
bsg_map_buffer(struct bsg_buffer * buf,struct request * req)201 static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
202 {
203 size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
204
205 BUG_ON(!req->nr_phys_segments);
206
207 buf->sg_list = kzalloc(sz, GFP_KERNEL);
208 if (!buf->sg_list)
209 return -ENOMEM;
210 sg_init_table(buf->sg_list, req->nr_phys_segments);
211 buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
212 buf->payload_len = blk_rq_bytes(req);
213 return 0;
214 }
215
216 /**
217 * bsg_prepare_job - create the bsg_job structure for the bsg request
218 * @dev: device that is being sent the bsg request
219 * @req: BSG request that needs a job structure
220 */
bsg_prepare_job(struct device * dev,struct request * req)221 static bool bsg_prepare_job(struct device *dev, struct request *req)
222 {
223 struct bsg_job *job = blk_mq_rq_to_pdu(req);
224 int ret;
225
226 job->timeout = req->timeout;
227
228 if (req->bio) {
229 ret = bsg_map_buffer(&job->request_payload, req);
230 if (ret)
231 goto failjob_rls_job;
232 }
233 if (job->bidi_rq) {
234 ret = bsg_map_buffer(&job->reply_payload, job->bidi_rq);
235 if (ret)
236 goto failjob_rls_rqst_payload;
237 }
238 job->dev = dev;
239 /* take a reference for the request */
240 get_device(job->dev);
241 kref_init(&job->kref);
242 return true;
243
244 failjob_rls_rqst_payload:
245 kfree(job->request_payload.sg_list);
246 failjob_rls_job:
247 job->result = -ENOMEM;
248 return false;
249 }
250
251 /**
252 * bsg_queue_rq - generic handler for bsg requests
253 * @hctx: hardware queue
254 * @bd: queue data
255 *
256 * On error the create_bsg_job function should return a -Exyz error value
257 * that will be set to ->result.
258 *
259 * Drivers/subsys should pass this to the queue init function.
260 */
bsg_queue_rq(struct blk_mq_hw_ctx * hctx,const struct blk_mq_queue_data * bd)261 static blk_status_t bsg_queue_rq(struct blk_mq_hw_ctx *hctx,
262 const struct blk_mq_queue_data *bd)
263 {
264 struct request_queue *q = hctx->queue;
265 struct device *dev = q->queuedata;
266 struct request *req = bd->rq;
267 struct bsg_set *bset =
268 container_of(q->tag_set, struct bsg_set, tag_set);
269 int sts = BLK_STS_IOERR;
270 int ret;
271
272 blk_mq_start_request(req);
273
274 if (!get_device(dev))
275 return BLK_STS_IOERR;
276
277 if (!bsg_prepare_job(dev, req))
278 goto out;
279
280 ret = bset->job_fn(blk_mq_rq_to_pdu(req));
281 if (!ret)
282 sts = BLK_STS_OK;
283
284 out:
285 put_device(dev);
286 return sts;
287 }
288
289 /* 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)290 static int bsg_init_rq(struct blk_mq_tag_set *set, struct request *req,
291 unsigned int hctx_idx, unsigned int numa_node)
292 {
293 struct bsg_job *job = blk_mq_rq_to_pdu(req);
294
295 job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL);
296 if (!job->reply)
297 return -ENOMEM;
298 return 0;
299 }
300
301 /* called right before the request is given to the request_queue user */
bsg_initialize_rq(struct request * req)302 static void bsg_initialize_rq(struct request *req)
303 {
304 struct bsg_job *job = blk_mq_rq_to_pdu(req);
305 void *reply = job->reply;
306
307 memset(job, 0, sizeof(*job));
308 job->reply = reply;
309 job->reply_len = SCSI_SENSE_BUFFERSIZE;
310 job->dd_data = job + 1;
311 }
312
bsg_exit_rq(struct blk_mq_tag_set * set,struct request * req,unsigned int hctx_idx)313 static void bsg_exit_rq(struct blk_mq_tag_set *set, struct request *req,
314 unsigned int hctx_idx)
315 {
316 struct bsg_job *job = blk_mq_rq_to_pdu(req);
317
318 kfree(job->reply);
319 }
320
bsg_remove_queue(struct request_queue * q)321 void bsg_remove_queue(struct request_queue *q)
322 {
323 if (q) {
324 struct bsg_set *bset =
325 container_of(q->tag_set, struct bsg_set, tag_set);
326
327 bsg_unregister_queue(q);
328 blk_cleanup_queue(q);
329 blk_mq_free_tag_set(&bset->tag_set);
330 kfree(bset);
331 }
332 }
333 EXPORT_SYMBOL_GPL(bsg_remove_queue);
334
bsg_timeout(struct request * rq,bool reserved)335 static enum blk_eh_timer_return bsg_timeout(struct request *rq, bool reserved)
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 .initialize_rq_fn = bsg_initialize_rq,
350 .complete = bsg_complete,
351 .timeout = bsg_timeout,
352 };
353
354 /**
355 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
356 * @dev: device to attach bsg device to
357 * @name: device to give bsg device
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 */
bsg_setup_queue(struct device * dev,const char * name,bsg_job_fn * job_fn,bsg_timeout_fn * timeout,int dd_job_size)362 struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
363 bsg_job_fn *job_fn, bsg_timeout_fn *timeout, int dd_job_size)
364 {
365 struct bsg_set *bset;
366 struct blk_mq_tag_set *set;
367 struct request_queue *q;
368 int ret = -ENOMEM;
369
370 bset = kzalloc(sizeof(*bset), GFP_KERNEL);
371 if (!bset)
372 return ERR_PTR(-ENOMEM);
373
374 bset->job_fn = job_fn;
375 bset->timeout_fn = timeout;
376
377 set = &bset->tag_set;
378 set->ops = &bsg_mq_ops,
379 set->nr_hw_queues = 1;
380 set->queue_depth = 128;
381 set->numa_node = NUMA_NO_NODE;
382 set->cmd_size = sizeof(struct bsg_job) + dd_job_size;
383 set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING;
384 if (blk_mq_alloc_tag_set(set))
385 goto out_tag_set;
386
387 q = blk_mq_init_queue(set);
388 if (IS_ERR(q)) {
389 ret = PTR_ERR(q);
390 goto out_queue;
391 }
392
393 q->queuedata = dev;
394 blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
395
396 ret = bsg_register_queue(q, dev, name, &bsg_transport_ops);
397 if (ret) {
398 printk(KERN_ERR "%s: bsg interface failed to "
399 "initialize - register queue\n", dev->kobj.name);
400 goto out_cleanup_queue;
401 }
402
403 return q;
404 out_cleanup_queue:
405 blk_cleanup_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
