[PATCH] dma-buf/sync-file: Avoid enable fence signaling if poll(.timeout=0)

[Gustavo Padovan]

Hi Chris,

2016-08-29 Chris Wilson <chris at chris-wilson.co.uk>:

> If we being polled with a timeout of zero, a nonblocking busy query,
> we don't need to install any fence callbacks as we will not be waiting.
> As we only install the callback once, the overhead comes from the atomic
> bit test that also causes serialisation between threads.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Sumit Semwal <sumit.semwal at linaro.org>
> Cc: Gustavo Padovan <gustavo at padovan.org>
> Cc: linux-media at vger.kernel.org
> Cc: dri-devel at lists.freedesktop.org
> Cc: linaro-mm-sig at lists.linaro.org
> ---
>  drivers/dma-buf/sync_file.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Indeed, we can shortcut this.

Reviewed-by: Gustavo Padovan <gustavo.padovan at collabora.co.uk>

Gustavo