1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Media device request objects
4 *
5 * Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
6 * Copyright (C) 2018 Intel Corporation
7 * Copyright (C) 2018 Google, Inc.
8 *
9 * Author: Hans Verkuil <hansverk@cisco.com>
10 * Author: Sakari Ailus <sakari.ailus@linux.intel.com>
11 */
12
13 #include <linux/anon_inodes.h>
14 #include <linux/file.h>
15 #include <linux/refcount.h>
16
17 #include <media/media-device.h>
18 #include <media/media-request.h>
19
20 static const char * const request_state[] = {
21 [MEDIA_REQUEST_STATE_IDLE] = "idle",
22 [MEDIA_REQUEST_STATE_VALIDATING] = "validating",
23 [MEDIA_REQUEST_STATE_QUEUED] = "queued",
24 [MEDIA_REQUEST_STATE_COMPLETE] = "complete",
25 [MEDIA_REQUEST_STATE_CLEANING] = "cleaning",
26 [MEDIA_REQUEST_STATE_UPDATING] = "updating",
27 };
28
29 static const char *
media_request_state_str(enum media_request_state state)30 media_request_state_str(enum media_request_state state)
31 {
32 BUILD_BUG_ON(ARRAY_SIZE(request_state) != NR_OF_MEDIA_REQUEST_STATE);
33
34 if (WARN_ON(state >= ARRAY_SIZE(request_state)))
35 return "invalid";
36 return request_state[state];
37 }
38
media_request_clean(struct media_request * req)39 static void media_request_clean(struct media_request *req)
40 {
41 struct media_request_object *obj, *obj_safe;
42
43 /* Just a sanity check. No other code path is allowed to change this. */
44 WARN_ON(req->state != MEDIA_REQUEST_STATE_CLEANING);
45 WARN_ON(req->updating_count);
46 WARN_ON(req->access_count);
47
48 list_for_each_entry_safe(obj, obj_safe, &req->objects, list) {
49 media_request_object_unbind(obj);
50 media_request_object_put(obj);
51 }
52
53 req->updating_count = 0;
54 req->access_count = 0;
55 WARN_ON(req->num_incomplete_objects);
56 req->num_incomplete_objects = 0;
57 wake_up_interruptible_all(&req->poll_wait);
58 }
59
media_request_release(struct kref * kref)60 static void media_request_release(struct kref *kref)
61 {
62 struct media_request *req =
63 container_of(kref, struct media_request, kref);
64 struct media_device *mdev = req->mdev;
65
66 dev_dbg(mdev->dev, "request: release %s\n", req->debug_str);
67
68 /* No other users, no need for a spinlock */
69 req->state = MEDIA_REQUEST_STATE_CLEANING;
70
71 media_request_clean(req);
72
73 if (mdev->ops->req_free)
74 mdev->ops->req_free(req);
75 else
76 kfree(req);
77 }
78
media_request_put(struct media_request * req)79 void media_request_put(struct media_request *req)
80 {
81 kref_put(&req->kref, media_request_release);
82 }
83 EXPORT_SYMBOL_GPL(media_request_put);
84
media_request_close(struct inode * inode,struct file * filp)85 static int media_request_close(struct inode *inode, struct file *filp)
86 {
87 struct media_request *req = filp->private_data;
88
89 media_request_put(req);
90 return 0;
91 }
92
media_request_poll(struct file * filp,struct poll_table_struct * wait)93 static __poll_t media_request_poll(struct file *filp,
94 struct poll_table_struct *wait)
95 {
96 struct media_request *req = filp->private_data;
97 unsigned long flags;
98 __poll_t ret = 0;
99
100 if (!(poll_requested_events(wait) & EPOLLPRI))
101 return 0;
102
103 poll_wait(filp, &req->poll_wait, wait);
104 spin_lock_irqsave(&req->lock, flags);
105 if (req->state == MEDIA_REQUEST_STATE_COMPLETE) {
106 ret = EPOLLPRI;
107 goto unlock;
108 }
109 if (req->state != MEDIA_REQUEST_STATE_QUEUED) {
110 ret = EPOLLERR;
111 goto unlock;
112 }
113
114 unlock:
115 spin_unlock_irqrestore(&req->lock, flags);
116 return ret;
117 }
118
media_request_ioctl_queue(struct media_request * req)119 static long media_request_ioctl_queue(struct media_request *req)
120 {
121 struct media_device *mdev = req->mdev;
122 enum media_request_state state;
123 unsigned long flags;
124 int ret;
125
126 dev_dbg(mdev->dev, "request: queue %s\n", req->debug_str);
127
128 /*
129 * Ensure the request that is validated will be the one that gets queued
130 * next by serialising the queueing process. This mutex is also used
131 * to serialize with canceling a vb2 queue and with setting values such
132 * as controls in a request.
133 */
134 mutex_lock(&mdev->req_queue_mutex);
135
136 media_request_get(req);
137
138 spin_lock_irqsave(&req->lock, flags);
139 if (req->state == MEDIA_REQUEST_STATE_IDLE)
140 req->state = MEDIA_REQUEST_STATE_VALIDATING;
141 state = req->state;
142 spin_unlock_irqrestore(&req->lock, flags);
143 if (state != MEDIA_REQUEST_STATE_VALIDATING) {
144 dev_dbg(mdev->dev,
145 "request: unable to queue %s, request in state %s\n",
146 req->debug_str, media_request_state_str(state));
147 media_request_put(req);
148 mutex_unlock(&mdev->req_queue_mutex);
149 return -EBUSY;
150 }
151
152 ret = mdev->ops->req_validate(req);
153
154 /*
155 * If the req_validate was successful, then we mark the state as QUEUED
156 * and call req_queue. The reason we set the state first is that this
157 * allows req_queue to unbind or complete the queued objects in case
158 * they are immediately 'consumed'. State changes from QUEUED to another
159 * state can only happen if either the driver changes the state or if
160 * the user cancels the vb2 queue. The driver can only change the state
161 * after each object is queued through the req_queue op (and note that
162 * that op cannot fail), so setting the state to QUEUED up front is
163 * safe.
164 *
165 * The other reason for changing the state is if the vb2 queue is
166 * canceled, and that uses the req_queue_mutex which is still locked
167 * while req_queue is called, so that's safe as well.
168 */
169 spin_lock_irqsave(&req->lock, flags);
170 req->state = ret ? MEDIA_REQUEST_STATE_IDLE
171 : MEDIA_REQUEST_STATE_QUEUED;
172 spin_unlock_irqrestore(&req->lock, flags);
173
174 if (!ret)
175 mdev->ops->req_queue(req);
176
177 mutex_unlock(&mdev->req_queue_mutex);
178
179 if (ret) {
180 dev_dbg(mdev->dev, "request: can't queue %s (%d)\n",
181 req->debug_str, ret);
182 media_request_put(req);
183 }
184
185 return ret;
186 }
187
media_request_ioctl_reinit(struct media_request * req)188 static long media_request_ioctl_reinit(struct media_request *req)
189 {
190 struct media_device *mdev = req->mdev;
191 unsigned long flags;
192
193 spin_lock_irqsave(&req->lock, flags);
194 if (req->state != MEDIA_REQUEST_STATE_IDLE &&
195 req->state != MEDIA_REQUEST_STATE_COMPLETE) {
196 dev_dbg(mdev->dev,
197 "request: %s not in idle or complete state, cannot reinit\n",
198 req->debug_str);
199 spin_unlock_irqrestore(&req->lock, flags);
200 return -EBUSY;
201 }
202 if (req->access_count) {
203 dev_dbg(mdev->dev,
204 "request: %s is being accessed, cannot reinit\n",
205 req->debug_str);
206 spin_unlock_irqrestore(&req->lock, flags);
207 return -EBUSY;
208 }
209 req->state = MEDIA_REQUEST_STATE_CLEANING;
210 spin_unlock_irqrestore(&req->lock, flags);
211
212 media_request_clean(req);
213
214 spin_lock_irqsave(&req->lock, flags);
215 req->state = MEDIA_REQUEST_STATE_IDLE;
216 spin_unlock_irqrestore(&req->lock, flags);
217
218 return 0;
219 }
220
media_request_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)221 static long media_request_ioctl(struct file *filp, unsigned int cmd,
222 unsigned long arg)
223 {
224 struct media_request *req = filp->private_data;
225
226 switch (cmd) {
227 case MEDIA_REQUEST_IOC_QUEUE:
228 return media_request_ioctl_queue(req);
229 case MEDIA_REQUEST_IOC_REINIT:
230 return media_request_ioctl_reinit(req);
231 default:
232 return -ENOIOCTLCMD;
233 }
234 }
235
236 static const struct file_operations request_fops = {
237 .owner = THIS_MODULE,
238 .poll = media_request_poll,
239 .unlocked_ioctl = media_request_ioctl,
240 #ifdef CONFIG_COMPAT
241 .compat_ioctl = media_request_ioctl,
242 #endif /* CONFIG_COMPAT */
243 .release = media_request_close,
244 };
245
246 struct media_request *
media_request_get_by_fd(struct media_device * mdev,int request_fd)247 media_request_get_by_fd(struct media_device *mdev, int request_fd)
248 {
249 struct media_request *req;
250
251 if (!mdev || !mdev->ops ||
252 !mdev->ops->req_validate || !mdev->ops->req_queue)
253 return ERR_PTR(-EBADR);
254
255 CLASS(fd, f)(request_fd);
256 if (fd_empty(f))
257 goto err;
258
259 if (fd_file(f)->f_op != &request_fops)
260 goto err;
261 req = fd_file(f)->private_data;
262 if (req->mdev != mdev)
263 goto err;
264
265 /*
266 * Note: as long as someone has an open filehandle of the request,
267 * the request can never be released. The fdget() above ensures that
268 * even if userspace closes the request filehandle, the release()
269 * fop won't be called, so the media_request_get() always succeeds
270 * and there is no race condition where the request was released
271 * before media_request_get() is called.
272 */
273 media_request_get(req);
274 return req;
275
276 err:
277 dev_dbg(mdev->dev, "cannot find request_fd %d\n", request_fd);
278 return ERR_PTR(-EINVAL);
279 }
280 EXPORT_SYMBOL_GPL(media_request_get_by_fd);
281
media_request_alloc(struct media_device * mdev,int * alloc_fd)282 int media_request_alloc(struct media_device *mdev, int *alloc_fd)
283 {
284 struct media_request *req;
285 struct file *filp;
286 int fd;
287 int ret;
288
289 /* Either both are NULL or both are non-NULL */
290 if (WARN_ON(!mdev->ops->req_alloc ^ !mdev->ops->req_free))
291 return -ENOMEM;
292
293 if (mdev->ops->req_alloc)
294 req = mdev->ops->req_alloc(mdev);
295 else
296 req = kzalloc(sizeof(*req), GFP_KERNEL);
297 if (!req)
298 return -ENOMEM;
299
300 fd = get_unused_fd_flags(O_CLOEXEC);
301 if (fd < 0) {
302 ret = fd;
303 goto err_free_req;
304 }
305
306 filp = anon_inode_getfile("request", &request_fops, NULL, O_CLOEXEC);
307 if (IS_ERR(filp)) {
308 ret = PTR_ERR(filp);
309 goto err_put_fd;
310 }
311
312 filp->private_data = req;
313 req->mdev = mdev;
314 req->state = MEDIA_REQUEST_STATE_IDLE;
315 req->num_incomplete_objects = 0;
316 kref_init(&req->kref);
317 INIT_LIST_HEAD(&req->objects);
318 spin_lock_init(&req->lock);
319 init_waitqueue_head(&req->poll_wait);
320 req->updating_count = 0;
321 req->access_count = 0;
322
323 *alloc_fd = fd;
324
325 snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d",
326 atomic_inc_return(&mdev->request_id), fd);
327 dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);
328
329 fd_install(fd, filp);
330
331 return 0;
332
333 err_put_fd:
334 put_unused_fd(fd);
335
336 err_free_req:
337 if (mdev->ops->req_free)
338 mdev->ops->req_free(req);
339 else
340 kfree(req);
341
342 return ret;
343 }
344
media_request_object_release(struct kref * kref)345 static void media_request_object_release(struct kref *kref)
346 {
347 struct media_request_object *obj =
348 container_of(kref, struct media_request_object, kref);
349 struct media_request *req = obj->req;
350
351 if (WARN_ON(req))
352 media_request_object_unbind(obj);
353 obj->ops->release(obj);
354 }
355
356 struct media_request_object *
media_request_object_find(struct media_request * req,const struct media_request_object_ops * ops,void * priv)357 media_request_object_find(struct media_request *req,
358 const struct media_request_object_ops *ops,
359 void *priv)
360 {
361 struct media_request_object *obj;
362 struct media_request_object *found = NULL;
363 unsigned long flags;
364
365 if (WARN_ON(!ops || !priv))
366 return NULL;
367
368 spin_lock_irqsave(&req->lock, flags);
369 list_for_each_entry(obj, &req->objects, list) {
370 if (obj->ops == ops && obj->priv == priv) {
371 media_request_object_get(obj);
372 found = obj;
373 break;
374 }
375 }
376 spin_unlock_irqrestore(&req->lock, flags);
377 return found;
378 }
379 EXPORT_SYMBOL_GPL(media_request_object_find);
380
media_request_object_put(struct media_request_object * obj)381 void media_request_object_put(struct media_request_object *obj)
382 {
383 kref_put(&obj->kref, media_request_object_release);
384 }
385 EXPORT_SYMBOL_GPL(media_request_object_put);
386
media_request_object_init(struct media_request_object * obj)387 void media_request_object_init(struct media_request_object *obj)
388 {
389 obj->ops = NULL;
390 obj->req = NULL;
391 obj->priv = NULL;
392 obj->completed = false;
393 INIT_LIST_HEAD(&obj->list);
394 kref_init(&obj->kref);
395 }
396 EXPORT_SYMBOL_GPL(media_request_object_init);
397
media_request_object_bind(struct media_request * req,const struct media_request_object_ops * ops,void * priv,bool is_buffer,struct media_request_object * obj)398 int media_request_object_bind(struct media_request *req,
399 const struct media_request_object_ops *ops,
400 void *priv, bool is_buffer,
401 struct media_request_object *obj)
402 {
403 unsigned long flags;
404 int ret = -EBUSY;
405
406 if (WARN_ON(!ops->release))
407 return -EBADR;
408
409 spin_lock_irqsave(&req->lock, flags);
410
411 if (WARN_ON(req->state != MEDIA_REQUEST_STATE_UPDATING &&
412 req->state != MEDIA_REQUEST_STATE_QUEUED))
413 goto unlock;
414
415 obj->req = req;
416 obj->ops = ops;
417 obj->priv = priv;
418
419 if (is_buffer)
420 list_add_tail(&obj->list, &req->objects);
421 else
422 list_add(&obj->list, &req->objects);
423 req->num_incomplete_objects++;
424 ret = 0;
425
426 unlock:
427 spin_unlock_irqrestore(&req->lock, flags);
428 return ret;
429 }
430 EXPORT_SYMBOL_GPL(media_request_object_bind);
431
media_request_object_unbind(struct media_request_object * obj)432 void media_request_object_unbind(struct media_request_object *obj)
433 {
434 struct media_request *req = obj->req;
435 unsigned long flags;
436 bool completed = false;
437
438 if (WARN_ON(!req))
439 return;
440
441 spin_lock_irqsave(&req->lock, flags);
442 list_del(&obj->list);
443 obj->req = NULL;
444
445 if (req->state == MEDIA_REQUEST_STATE_COMPLETE)
446 goto unlock;
447
448 if (WARN_ON(req->state == MEDIA_REQUEST_STATE_VALIDATING))
449 goto unlock;
450
451 if (req->state == MEDIA_REQUEST_STATE_CLEANING) {
452 if (!obj->completed)
453 req->num_incomplete_objects--;
454 goto unlock;
455 }
456
457 if (WARN_ON(!req->num_incomplete_objects))
458 goto unlock;
459
460 req->num_incomplete_objects--;
461 if (req->state == MEDIA_REQUEST_STATE_QUEUED &&
462 !req->num_incomplete_objects) {
463 req->state = MEDIA_REQUEST_STATE_COMPLETE;
464 completed = true;
465 wake_up_interruptible_all(&req->poll_wait);
466 }
467
468 unlock:
469 spin_unlock_irqrestore(&req->lock, flags);
470 if (obj->ops->unbind)
471 obj->ops->unbind(obj);
472 if (completed)
473 media_request_put(req);
474 }
475 EXPORT_SYMBOL_GPL(media_request_object_unbind);
476
media_request_object_complete(struct media_request_object * obj)477 void media_request_object_complete(struct media_request_object *obj)
478 {
479 struct media_request *req = obj->req;
480 unsigned long flags;
481 bool completed = false;
482
483 spin_lock_irqsave(&req->lock, flags);
484 if (obj->completed)
485 goto unlock;
486 obj->completed = true;
487 if (WARN_ON(!req->num_incomplete_objects) ||
488 WARN_ON(req->state != MEDIA_REQUEST_STATE_QUEUED))
489 goto unlock;
490
491 if (!--req->num_incomplete_objects) {
492 req->state = MEDIA_REQUEST_STATE_COMPLETE;
493 wake_up_interruptible_all(&req->poll_wait);
494 completed = true;
495 }
496 unlock:
497 spin_unlock_irqrestore(&req->lock, flags);
498 if (completed)
499 media_request_put(req);
500 }
501 EXPORT_SYMBOL_GPL(media_request_object_complete);
502