Re: [PATCH 1/1] media: saa7146: don't use mutex_lock_interruptible() in device_release().

From: Hans Verkuil
Date: Tue Dec 11 2012 - 02:22:57 EST


On Tue December 11 2012 04:05:28 Cyril Roelandt wrote:
> Use uninterruptible mutex_lock in the release() file op to make sure all
> resources are properly freed when a process is being terminated. Returning
> -ERESTARTSYS has no effect for a terminating process and this may cause driver
> resources not to be released.

Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>

Thanks!

Hans

> This was found using the following semantic patch (http://coccinelle.lip6.fr/):
>
> <spml>
> @r@
> identifier fops;
> identifier release_func;
> @@
> static const struct v4l2_file_operations fops = {
> .release = release_func
> };
>
> @depends on r@
> identifier r.release_func;
> expression E;
> @@
> static int release_func(...)
> {
> ...
> - if (mutex_lock_interruptible(E)) return -ERESTARTSYS;
> + mutex_lock(E);
> ...
> }
> </spml>
>
> Signed-off-by: Cyril Roelandt <tipecaml@xxxxxxxxx>
> ---
> drivers/media/common/saa7146/saa7146_fops.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/media/common/saa7146/saa7146_fops.c b/drivers/media/common/saa7146/saa7146_fops.c
> index b3890bd..0afe98d 100644
> --- a/drivers/media/common/saa7146/saa7146_fops.c
> +++ b/drivers/media/common/saa7146/saa7146_fops.c
> @@ -265,8 +265,7 @@ static int fops_release(struct file *file)
>
> DEB_EE("file:%p\n", file);
>
> - if (mutex_lock_interruptible(vdev->lock))
> - return -ERESTARTSYS;
> + mutex_lock(vdev->lock);
>
> if (vdev->vfl_type == VFL_TYPE_VBI) {
> if (dev->ext_vv_data->capabilities & V4L2_CAP_VBI_CAPTURE)
>
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