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@xxxxxxx>
---
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);
--
2.17.1
