Re: [PATCH 03/11] drm/msm: Remove call to reservation_object_test_signaled_rcu before wait

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Aug 29, 2016 at 08:08:26AM +0100, Chris Wilson wrote:
> Since fence_wait_timeout_reservation_object_wait_timeout_rcu() with a
> timeout of 0 becomes reservation_object_test_signaled_rcu(), we do not
> need to handle such conversion in the caller. The only challenge are
> those callers that wish to differentiate the error code between the
> nonblocking busy check and potentially blocking wait.
> 
> v2: 9 is only 0 in German.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Rob Clark <robdclark@gmail.com>

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/msm/msm_gem.c | 22 ++++++++++------------
>  1 file changed, 10 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> index 6cd4af443139..45796a88d353 100644
> --- a/drivers/gpu/drm/msm/msm_gem.c
> +++ b/drivers/gpu/drm/msm/msm_gem.c
> @@ -584,18 +584,16 @@ int msm_gem_cpu_prep(struct drm_gem_object *obj, uint32_t op, ktime_t *timeout)
>  {
>  	struct msm_gem_object *msm_obj = to_msm_bo(obj);
>  	bool write = !!(op & MSM_PREP_WRITE);
> -
> -	if (op & MSM_PREP_NOSYNC) {
> -		if (!reservation_object_test_signaled_rcu(msm_obj->resv, write))
> -			return -EBUSY;
> -	} else {
> -		int ret;
> -
> -		ret = reservation_object_wait_timeout_rcu(msm_obj->resv, write,
> -				true, timeout_to_jiffies(timeout));
> -		if (ret <= 0)
> -			return ret == 0 ? -ETIMEDOUT : ret;
> -	}
> +	unsigned long remain =
> +		op & MSG_PREP_NOSYNC ? 0 : timeout_to_jiffies(timeout);
> +	long ret;
> +
> +	ret = reservation_object_wait_timeout_rcu(msm_obj->resv, write,
> +						  true,  remain);
> +	if (ret == 0)
> +		return remain == 0 ? -EBUSY : -ETIMEDOUT;
> +	else if (ret < 0)
> +		return ret;
>  
>  	/* TODO cache maintenance */
>  
> -- 
> 2.9.3
> 
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> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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