Commit 93505ee7 authored by Christian König's avatar Christian König
Browse files

dma-buf: fix busy wait for new shared fences 



When reservation_object_add_shared_fence is replacing an old fence with a new
one we should not drop the old one before the new one is in place.

Otherwise other cores can busy wait for the new one to appear.

Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/322030/
parent 178e5f3a

drivers/dma-buf/reservation.c

+7 −7
Original line number Diff line number Diff line
@@ -196,6 +196,7 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, 
					 struct dma_fence *fence)

{

	struct reservation_object_list *fobj;

	struct dma_fence *old;

	unsigned int i, count;



	dma_fence_get(fence);
@@ -209,18 +210,16 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, 
	write_seqcount_begin(&obj->seq);



	for (i = 0; i < count; ++i) {

		struct dma_fence *old_fence;



		old_fence = rcu_dereference_protected(fobj->shared[i],

		old = rcu_dereference_protected(fobj->shared[i],

						reservation_object_held(obj));

		if (old_fence->context == fence->context ||

		    dma_fence_is_signaled(old_fence)) {

			dma_fence_put(old_fence);

		if (old->context == fence->context ||

		    dma_fence_is_signaled(old))

			goto replace;

	}

	}



	BUG_ON(fobj->shared_count >= fobj->shared_max);

	old = NULL;

	count++;



replace:
@@ -230,6 +229,7 @@ replace: 


	write_seqcount_end(&obj->seq);

	preempt_enable();

	dma_fence_put(old);

}

EXPORT_SYMBOL(reservation_object_add_shared_fence);

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