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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * v4l2-fh.c4 *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(&fh->list);27 set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);28 /*29 * determine_valid_ioctls() does not know if struct v4l2_fh30 * is used by this driver, but here we do. So enable the31 * 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}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(fh->vdev->prio, &fh->prio);49 spin_lock_irqsave(&fh->vdev->fh_lock, flags);50 list_add(&fh->list, &fh->vdev->fh_list);51 spin_unlock_irqrestore(&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(filp);58 struct v4l2_fh *fh = kzalloc(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(&fh->list);75 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);76 v4l2_prio_close(fh->vdev->prio, 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(fh->vdev);85 v4l2_event_unsubscribe_all(fh);86 mutex_destroy(&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(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(&fh->list);114 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);115 return is_singular;116}117EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);118