[5/17] drivers/media/video/pvrusb2: Add missing mutex_unlock

  From: Julia Lawall <julia@diku.dk>

Add a mutex_unlock missing on the error path.  In the other functions in
the same file the locks and unlocks of this mutex appear to be balanced,
so it would seem that the same should hold in this case.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression E1;
@@

* mutex_lock(E1,...);
  <+... when != E1
  if (...) {
    ... when != E1
*   return ...;
  }
  ...+>
* mutex_unlock(E1,...);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
 drivers/media/video/pvrusb2/pvrusb2-ioread.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
  

I looked through my revision history and that bug has been there in the 
driver source since at least May 2005, long before it was ever merged 
into the kernel.  Wow, what a great catch.  Thanks!

Acked-By: Mike Isely <isely@pobox.com>

  -Mike


On Wed, 26 May 2010, Julia Lawall wrote:

> From: Julia Lawall <julia@diku.dk>
> 
> Add a mutex_unlock missing on the error path.  In the other functions in
> the same file the locks and unlocks of this mutex appear to be balanced,
> so it would seem that the same should hold in this case.
> 
> The semantic match that finds this problem is as follows:
> (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @@
> expression E1;
> @@
> 
> * mutex_lock(E1,...);
>   <+... when != E1
>   if (...) {
>     ... when != E1
> *   return ...;
>   }
>   ...+>
> * mutex_unlock(E1,...);
> // </smpl>
> 
> Signed-off-by: Julia Lawall <julia@diku.dk>
> 
> ---
>  drivers/media/video/pvrusb2/pvrusb2-ioread.c |    5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/video/pvrusb2/pvrusb2-ioread.c b/drivers/media/video/pvrusb2/pvrusb2-ioread.c
> index b482478..bba6115 100644
> --- a/drivers/media/video/pvrusb2/pvrusb2-ioread.c
> +++ b/drivers/media/video/pvrusb2/pvrusb2-ioread.c
> @@ -223,7 +223,10 @@ int pvr2_ioread_setup(struct pvr2_ioread *cp,struct pvr2_stream *sp)
>  				   " pvr2_ioread_setup (setup) id=%p",cp);
>  			pvr2_stream_kill(sp);
>  			ret = pvr2_stream_set_buffer_count(sp,BUFFER_COUNT);
> -			if (ret < 0) return ret;
> +			if (ret < 0) {
> +				mutex_unlock(&cp->mutex);
> +				return ret;
> +			}
>  			for (idx = 0; idx < BUFFER_COUNT; idx++) {
>  				bp = pvr2_stream_get_buffer(sp,idx);
>  				pvr2_buffer_set_buffer(bp,
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>