Re: [Intel-gfx] [PATCH 02/28] drm/i915: use new iterator in i915_gem_object_wait_reservation

["Christian König" <christian.koenig@amd.com>]

Am 21.10.21 um 12:35 schrieb Maarten Lankhorst:
> From: Christian König <christian.koenig@amd.com>
>
> Simplifying the code a bit.
>
> Signed-off-by: Christian König <christian.koenig@amd.com>
> [mlankhorst: Handle timeout = 0 correctly, use new i915_request_wait_timeout.]
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

LGTM, do you want to push it or should I pick it up into drm-misc-next?

Christian.

> ---
>   drivers/gpu/drm/i915/gem/i915_gem_wait.c | 65 ++++++++----------------
>   1 file changed, 20 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_wait.c b/drivers/gpu/drm/i915/gem/i915_gem_wait.c
> index f909aaa09d9c..840c13706999 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_wait.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_wait.c
> @@ -25,7 +25,7 @@ i915_gem_object_wait_fence(struct dma_fence *fence,
>   		return timeout;
>   
>   	if (dma_fence_is_i915(fence))
> -		return i915_request_wait(to_request(fence), flags, timeout);
> +		return i915_request_wait_timeout(to_request(fence), flags, timeout);
>   
>   	return dma_fence_wait_timeout(fence,
>   				      flags & I915_WAIT_INTERRUPTIBLE,
> @@ -37,58 +37,29 @@ i915_gem_object_wait_reservation(struct dma_resv *resv,
>   				 unsigned int flags,
>   				 long timeout)
>   {
> -	struct dma_fence *excl;
> -	bool prune_fences = false;
> -
> -	if (flags & I915_WAIT_ALL) {
> -		struct dma_fence **shared;
> -		unsigned int count, i;
> -		int ret;
> -
> -		ret = dma_resv_get_fences(resv, &excl, &count, &shared);
> -		if (ret)
> -			return ret;
> -
> -		for (i = 0; i < count; i++) {
> -			timeout = i915_gem_object_wait_fence(shared[i],
> -							     flags, timeout);
> -			if (timeout < 0)
> -				break;
> -
> -			dma_fence_put(shared[i]);
> -		}
> -
> -		for (; i < count; i++)
> -			dma_fence_put(shared[i]);
> -		kfree(shared);
> +	struct dma_resv_iter cursor;
> +	struct dma_fence *fence;
> +	long ret = timeout ?: 1;
> +
> +	dma_resv_iter_begin(&cursor, resv, flags & I915_WAIT_ALL);
> +	dma_resv_for_each_fence_unlocked(&cursor, fence) {
> +		ret = i915_gem_object_wait_fence(fence, flags, timeout);
> +		if (ret <= 0)
> +			break;
>   
> -		/*
> -		 * If both shared fences and an exclusive fence exist,
> -		 * then by construction the shared fences must be later
> -		 * than the exclusive fence. If we successfully wait for
> -		 * all the shared fences, we know that the exclusive fence
> -		 * must all be signaled. If all the shared fences are
> -		 * signaled, we can prune the array and recover the
> -		 * floating references on the fences/requests.
> -		 */
> -		prune_fences = count && timeout >= 0;
> -	} else {
> -		excl = dma_resv_get_excl_unlocked(resv);
> +		if (timeout)
> +			timeout = ret;
>   	}
> -
> -	if (excl && timeout >= 0)
> -		timeout = i915_gem_object_wait_fence(excl, flags, timeout);
> -
> -	dma_fence_put(excl);
> +	dma_resv_iter_end(&cursor);
>   
>   	/*
>   	 * Opportunistically prune the fences iff we know they have *all* been
>   	 * signaled.
>   	 */
> -	if (prune_fences)
> +	if (timeout > 0)
>   		dma_resv_prune(resv);
>   
> -	return timeout;
> +	return ret;
>   }
>   
>   static void fence_set_priority(struct dma_fence *fence,
> @@ -196,7 +167,11 @@ i915_gem_object_wait(struct drm_i915_gem_object *obj,
>   
>   	timeout = i915_gem_object_wait_reservation(obj->base.resv,
>   						   flags, timeout);
> -	return timeout < 0 ? timeout : 0;
> +
> +	if (timeout < 0)
> +		return timeout;
> +
> +	return !timeout ? -ETIME : 0;
>   }
>   
>   static inline unsigned long nsecs_to_jiffies_timeout(const u64 n)