1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * v4l2-fh.c
4 *
5 * V4L2 file handles.
6 *
7 * Copyright (C) 2009--2010 Nokia Corporation.
8 *
9 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
10 */
11
12#include <linux/bitops.h>
13#include <linux/slab.h>
14#include <linux/export.h>
15#include <media/v4l2-dev.h>
16#include <media/v4l2-fh.h>
17#include <media/v4l2-event.h>
18#include <media/v4l2-ioctl.h>
19#include <media/v4l2-mc.h>
20
21void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
22{
23 fh->vdev = vdev;
24 /* Inherit from video_device. May be overridden by the driver. */
25 fh->ctrl_handler = vdev->ctrl_handler;
26 INIT_LIST_HEAD(list: &fh->list);
27 set_bit(nr: V4L2_FL_USES_V4L2_FH, addr: &fh->vdev->flags);
28 /*
29 * determine_valid_ioctls() does not know if struct v4l2_fh
30 * is used by this driver, but here we do. So enable the
31 * prio ioctls here.
32 */
33 set_bit(_IOC_NR(VIDIOC_G_PRIORITY), addr: vdev->valid_ioctls);
34 set_bit(_IOC_NR(VIDIOC_S_PRIORITY), addr: vdev->valid_ioctls);
35 fh->prio = V4L2_PRIORITY_UNSET;
36 init_waitqueue_head(&fh->wait);
37 INIT_LIST_HEAD(list: &fh->available);
38 INIT_LIST_HEAD(list: &fh->subscribed);
39 fh->sequence = -1;
40 mutex_init(&fh->subscribe_lock);
41}
42EXPORT_SYMBOL_GPL(v4l2_fh_init);
43
44void v4l2_fh_add(struct v4l2_fh *fh)
45{
46 unsigned long flags;
47
48 v4l2_prio_open(global: fh->vdev->prio, local: &fh->prio);
49 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
50 list_add(new: &fh->list, head: &fh->vdev->fh_list);
51 spin_unlock_irqrestore(lock: &fh->vdev->fh_lock, flags);
52}
53EXPORT_SYMBOL_GPL(v4l2_fh_add);
54
55int v4l2_fh_open(struct file *filp)
56{
57 struct video_device *vdev = video_devdata(file: filp);
58 struct v4l2_fh *fh = kzalloc(size: sizeof(*fh), GFP_KERNEL);
59
60 filp->private_data = fh;
61 if (fh == NULL)
62 return -ENOMEM;
63 v4l2_fh_init(fh, vdev);
64 v4l2_fh_add(fh);
65 return 0;
66}
67EXPORT_SYMBOL_GPL(v4l2_fh_open);
68
69void v4l2_fh_del(struct v4l2_fh *fh)
70{
71 unsigned long flags;
72
73 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
74 list_del_init(entry: &fh->list);
75 spin_unlock_irqrestore(lock: &fh->vdev->fh_lock, flags);
76 v4l2_prio_close(global: fh->vdev->prio, local: fh->prio);
77}
78EXPORT_SYMBOL_GPL(v4l2_fh_del);
79
80void v4l2_fh_exit(struct v4l2_fh *fh)
81{
82 if (fh->vdev == NULL)
83 return;
84 v4l_disable_media_source(vdev: fh->vdev);
85 v4l2_event_unsubscribe_all(fh);
86 mutex_destroy(lock: &fh->subscribe_lock);
87 fh->vdev = NULL;
88}
89EXPORT_SYMBOL_GPL(v4l2_fh_exit);
90
91int v4l2_fh_release(struct file *filp)
92{
93 struct v4l2_fh *fh = filp->private_data;
94
95 if (fh) {
96 v4l2_fh_del(fh);
97 v4l2_fh_exit(fh);
98 kfree(objp: fh);
99 filp->private_data = NULL;
100 }
101 return 0;
102}
103EXPORT_SYMBOL_GPL(v4l2_fh_release);
104
105int v4l2_fh_is_singular(struct v4l2_fh *fh)
106{
107 unsigned long flags;
108 int is_singular;
109
110 if (fh == NULL || fh->vdev == NULL)
111 return 0;
112 spin_lock_irqsave(&fh->vdev->fh_lock, flags);
113 is_singular = list_is_singular(head: &fh->list);
114 spin_unlock_irqrestore(lock: &fh->vdev->fh_lock, flags);
115 return is_singular;
116}
117EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
118

source code of linux/drivers/media/v4l2-core/v4l2-fh.c