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 <hans.verkuil@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
20static 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
29static const char *
30media_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
39static 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
60static 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(objp: req);
77}
78
79void media_request_put(struct media_request *req)
80{
81 kref_put(kref: &req->kref, release: media_request_release);
82}
83EXPORT_SYMBOL_GPL(media_request_put);
84
85static 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
93static __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(p: wait) & EPOLLPRI))
101 return 0;
102
103 poll_wait(filp, wait_address: &req->poll_wait, p: 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
114unlock:
115 spin_unlock_irqrestore(lock: &req->lock, flags);
116 return ret;
117}
118
119static 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(lock: &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(lock: &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(lock: &req->lock, flags);
173
174 if (!ret)
175 mdev->ops->req_queue(req);
176
177 mutex_unlock(lock: &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
188static 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(lock: &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(lock: &req->lock, flags);
207 return -EBUSY;
208 }
209 req->state = MEDIA_REQUEST_STATE_CLEANING;
210 spin_unlock_irqrestore(lock: &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(lock: &req->lock, flags);
217
218 return 0;
219}
220
221static 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
236static 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
246struct media_request *
247media_request_get_by_fd(struct media_device *mdev, int request_fd)
248{
249 struct fd f;
250 struct media_request *req;
251
252 if (!mdev || !mdev->ops ||
253 !mdev->ops->req_validate || !mdev->ops->req_queue)
254 return ERR_PTR(error: -EBADR);
255
256 f = fdget(fd: request_fd);
257 if (!f.file)
258 goto err_no_req_fd;
259
260 if (f.file->f_op != &request_fops)
261 goto err_fput;
262 req = f.file->private_data;
263 if (req->mdev != mdev)
264 goto err_fput;
265
266 /*
267 * Note: as long as someone has an open filehandle of the request,
268 * the request can never be released. The fdget() above ensures that
269 * even if userspace closes the request filehandle, the release()
270 * fop won't be called, so the media_request_get() always succeeds
271 * and there is no race condition where the request was released
272 * before media_request_get() is called.
273 */
274 media_request_get(req);
275 fdput(fd: f);
276
277 return req;
278
279err_fput:
280 fdput(fd: f);
281
282err_no_req_fd:
283 dev_dbg(mdev->dev, "cannot find request_fd %d\n", request_fd);
284 return ERR_PTR(error: -EINVAL);
285}
286EXPORT_SYMBOL_GPL(media_request_get_by_fd);
287
288int media_request_alloc(struct media_device *mdev, int *alloc_fd)
289{
290 struct media_request *req;
291 struct file *filp;
292 int fd;
293 int ret;
294
295 /* Either both are NULL or both are non-NULL */
296 if (WARN_ON(!mdev->ops->req_alloc ^ !mdev->ops->req_free))
297 return -ENOMEM;
298
299 if (mdev->ops->req_alloc)
300 req = mdev->ops->req_alloc(mdev);
301 else
302 req = kzalloc(size: sizeof(*req), GFP_KERNEL);
303 if (!req)
304 return -ENOMEM;
305
306 fd = get_unused_fd_flags(O_CLOEXEC);
307 if (fd < 0) {
308 ret = fd;
309 goto err_free_req;
310 }
311
312 filp = anon_inode_getfile(name: "request", fops: &request_fops, NULL, O_CLOEXEC);
313 if (IS_ERR(ptr: filp)) {
314 ret = PTR_ERR(ptr: filp);
315 goto err_put_fd;
316 }
317
318 filp->private_data = req;
319 req->mdev = mdev;
320 req->state = MEDIA_REQUEST_STATE_IDLE;
321 req->num_incomplete_objects = 0;
322 kref_init(kref: &req->kref);
323 INIT_LIST_HEAD(list: &req->objects);
324 spin_lock_init(&req->lock);
325 init_waitqueue_head(&req->poll_wait);
326 req->updating_count = 0;
327 req->access_count = 0;
328
329 *alloc_fd = fd;
330
331 snprintf(buf: req->debug_str, size: sizeof(req->debug_str), fmt: "%u:%d",
332 atomic_inc_return(v: &mdev->request_id), fd);
333 dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);
334
335 fd_install(fd, file: filp);
336
337 return 0;
338
339err_put_fd:
340 put_unused_fd(fd);
341
342err_free_req:
343 if (mdev->ops->req_free)
344 mdev->ops->req_free(req);
345 else
346 kfree(objp: req);
347
348 return ret;
349}
350
351static void media_request_object_release(struct kref *kref)
352{
353 struct media_request_object *obj =
354 container_of(kref, struct media_request_object, kref);
355 struct media_request *req = obj->req;
356
357 if (WARN_ON(req))
358 media_request_object_unbind(obj);
359 obj->ops->release(obj);
360}
361
362struct media_request_object *
363media_request_object_find(struct media_request *req,
364 const struct media_request_object_ops *ops,
365 void *priv)
366{
367 struct media_request_object *obj;
368 struct media_request_object *found = NULL;
369 unsigned long flags;
370
371 if (WARN_ON(!ops || !priv))
372 return NULL;
373
374 spin_lock_irqsave(&req->lock, flags);
375 list_for_each_entry(obj, &req->objects, list) {
376 if (obj->ops == ops && obj->priv == priv) {
377 media_request_object_get(obj);
378 found = obj;
379 break;
380 }
381 }
382 spin_unlock_irqrestore(lock: &req->lock, flags);
383 return found;
384}
385EXPORT_SYMBOL_GPL(media_request_object_find);
386
387void media_request_object_put(struct media_request_object *obj)
388{
389 kref_put(kref: &obj->kref, release: media_request_object_release);
390}
391EXPORT_SYMBOL_GPL(media_request_object_put);
392
393void media_request_object_init(struct media_request_object *obj)
394{
395 obj->ops = NULL;
396 obj->req = NULL;
397 obj->priv = NULL;
398 obj->completed = false;
399 INIT_LIST_HEAD(list: &obj->list);
400 kref_init(kref: &obj->kref);
401}
402EXPORT_SYMBOL_GPL(media_request_object_init);
403
404int media_request_object_bind(struct media_request *req,
405 const struct media_request_object_ops *ops,
406 void *priv, bool is_buffer,
407 struct media_request_object *obj)
408{
409 unsigned long flags;
410 int ret = -EBUSY;
411
412 if (WARN_ON(!ops->release))
413 return -EBADR;
414
415 spin_lock_irqsave(&req->lock, flags);
416
417 if (WARN_ON(req->state != MEDIA_REQUEST_STATE_UPDATING &&
418 req->state != MEDIA_REQUEST_STATE_QUEUED))
419 goto unlock;
420
421 obj->req = req;
422 obj->ops = ops;
423 obj->priv = priv;
424
425 if (is_buffer)
426 list_add_tail(new: &obj->list, head: &req->objects);
427 else
428 list_add(new: &obj->list, head: &req->objects);
429 req->num_incomplete_objects++;
430 ret = 0;
431
432unlock:
433 spin_unlock_irqrestore(lock: &req->lock, flags);
434 return ret;
435}
436EXPORT_SYMBOL_GPL(media_request_object_bind);
437
438void media_request_object_unbind(struct media_request_object *obj)
439{
440 struct media_request *req = obj->req;
441 unsigned long flags;
442 bool completed = false;
443
444 if (WARN_ON(!req))
445 return;
446
447 spin_lock_irqsave(&req->lock, flags);
448 list_del(entry: &obj->list);
449 obj->req = NULL;
450
451 if (req->state == MEDIA_REQUEST_STATE_COMPLETE)
452 goto unlock;
453
454 if (WARN_ON(req->state == MEDIA_REQUEST_STATE_VALIDATING))
455 goto unlock;
456
457 if (req->state == MEDIA_REQUEST_STATE_CLEANING) {
458 if (!obj->completed)
459 req->num_incomplete_objects--;
460 goto unlock;
461 }
462
463 if (WARN_ON(!req->num_incomplete_objects))
464 goto unlock;
465
466 req->num_incomplete_objects--;
467 if (req->state == MEDIA_REQUEST_STATE_QUEUED &&
468 !req->num_incomplete_objects) {
469 req->state = MEDIA_REQUEST_STATE_COMPLETE;
470 completed = true;
471 wake_up_interruptible_all(&req->poll_wait);
472 }
473
474unlock:
475 spin_unlock_irqrestore(lock: &req->lock, flags);
476 if (obj->ops->unbind)
477 obj->ops->unbind(obj);
478 if (completed)
479 media_request_put(req);
480}
481EXPORT_SYMBOL_GPL(media_request_object_unbind);
482
483void media_request_object_complete(struct media_request_object *obj)
484{
485 struct media_request *req = obj->req;
486 unsigned long flags;
487 bool completed = false;
488
489 spin_lock_irqsave(&req->lock, flags);
490 if (obj->completed)
491 goto unlock;
492 obj->completed = true;
493 if (WARN_ON(!req->num_incomplete_objects) ||
494 WARN_ON(req->state != MEDIA_REQUEST_STATE_QUEUED))
495 goto unlock;
496
497 if (!--req->num_incomplete_objects) {
498 req->state = MEDIA_REQUEST_STATE_COMPLETE;
499 wake_up_interruptible_all(&req->poll_wait);
500 completed = true;
501 }
502unlock:
503 spin_unlock_irqrestore(lock: &req->lock, flags);
504 if (completed)
505 media_request_put(req);
506}
507EXPORT_SYMBOL_GPL(media_request_object_complete);
508

source code of linux/drivers/media/mc/mc-request.c