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: Christian König christian.koenig@amd.com --- drivers/dma-buf/reservation.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c index c71b85c8c159..d59207ca72d2 100644 --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -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], - reservation_object_held(obj)); - if (old_fence->context == fence->context || - dma_fence_is_signaled(old_fence)) { - dma_fence_put(old_fence); + old = rcu_dereference_protected(fobj->shared[i], + reservation_object_held(obj)); + 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 @@ void reservation_object_add_shared_fence(struct reservation_object *obj,
write_seqcount_end(&obj->seq); preempt_enable(); + dma_fence_put(old); } EXPORT_SYMBOL(reservation_object_add_shared_fence);