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media: v4l2-core: push taking ioctl mutex down to ioctl handler

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The ioctl serialization mutex (vdev->lock or q->lock for vb2 queues)
was taken at the highest level in v4l2-dev.c. This prevents more
fine-grained locking since at that level we cannot examine the ioctl
arguments, we can only do that after video_usercopy is called.

So push the locking down to __video_do_ioctl() and subdev_do_ioctl_lock().

This also allows us to make a few functions in v4l2-ioctl.c static and
video_usercopy() is no longer exported.

The locking scheme is not changed by this patch, just pushed down.

Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Hans Verkuil 2018-05-11 05:32:24 -04:00 • committed by Mauro Carvalho Chehab
parent eba09b5b3d
commit 73a110623e
5 changed files with 33 additions and 31 deletions
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6
drivers/media/v4l2-core/v4l2-dev.c
View file

@ -360,14 +360,8 @@ static long v4l2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
int ret = -ENODEV;
if (vdev->fops->unlocked_ioctl) {
struct mutex *lock = v4l2_ioctl_get_lock(vdev, cmd);
if (lock && mutex_lock_interruptible(lock))
return -ERESTARTSYS;
if (video_is_registered(vdev))
ret = vdev->fops->unlocked_ioctl(filp, cmd, arg);
if (lock)
mutex_unlock(lock);
} else
ret = -ENOTTY;