GNU Linux-libre 5.10.219-gnu1
[releases.git] / block / bsg-lib.c
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
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
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
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
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  */
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
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
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  */
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  */
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
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  */
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  */
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 */
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 */
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
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
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
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  */
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);