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 21 void 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(&fh->list); 27 set_bit(V4L2_FL_USES_V4L2_FH, &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), vdev->valid_ioctls); 34 set_bit(_IOC_NR(VIDIOC_S_PRIORITY), vdev->valid_ioctls); 35 fh->prio = V4L2_PRIORITY_UNSET; 36 init_waitqueue_head(&fh->wait); 37 INIT_LIST_HEAD(&fh->available); 38 INIT_LIST_HEAD(&fh->subscribed); 39 fh->sequence = -1; 40 mutex_init(&fh->subscribe_lock); 41 } 42 EXPORT_SYMBOL_GPL(v4l2_fh_init); 43 44 void v4l2_fh_add(struct v4l2_fh *fh, struct file *filp) 45 { 46 unsigned long flags; 47 48 filp->private_data = fh; 49 50 v4l2_prio_open(fh->vdev->prio, &fh->prio); 51 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 52 list_add(&fh->list, &fh->vdev->fh_list); 53 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 54 } 55 EXPORT_SYMBOL_GPL(v4l2_fh_add); 56 57 int v4l2_fh_open(struct file *filp) 58 { 59 struct video_device *vdev = video_devdata(filp); 60 struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL); 61 62 if (fh == NULL) 63 return -ENOMEM; 64 v4l2_fh_init(fh, vdev); 65 v4l2_fh_add(fh, filp); 66 return 0; 67 } 68 EXPORT_SYMBOL_GPL(v4l2_fh_open); 69 70 void v4l2_fh_del(struct v4l2_fh *fh, struct file *filp) 71 { 72 unsigned long flags; 73 74 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 75 list_del_init(&fh->list); 76 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 77 v4l2_prio_close(fh->vdev->prio, fh->prio); 78 79 filp->private_data = NULL; 80 } 81 EXPORT_SYMBOL_GPL(v4l2_fh_del); 82 83 void v4l2_fh_exit(struct v4l2_fh *fh) 84 { 85 if (fh->vdev == NULL) 86 return; 87 v4l_disable_media_source(fh->vdev); 88 v4l2_event_unsubscribe_all(fh); 89 mutex_destroy(&fh->subscribe_lock); 90 fh->vdev = NULL; 91 } 92 EXPORT_SYMBOL_GPL(v4l2_fh_exit); 93 94 int v4l2_fh_release(struct file *filp) 95 { 96 struct v4l2_fh *fh = file_to_v4l2_fh(filp); 97 98 if (fh) { 99 v4l2_fh_del(fh, filp); 100 v4l2_fh_exit(fh); 101 kfree(fh); 102 } 103 return 0; 104 } 105 EXPORT_SYMBOL_GPL(v4l2_fh_release); 106 107 int v4l2_fh_is_singular(struct v4l2_fh *fh) 108 { 109 unsigned long flags; 110 int is_singular; 111 112 if (fh == NULL || fh->vdev == NULL) 113 return 0; 114 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 115 is_singular = list_is_singular(&fh->list); 116 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 117 return is_singular; 118 } 119 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular); 120