reservation: add reservation_object_get_excl_rcu() (824815c4) · Commits · 戴 / test

In the atomic modesetting path, each driver simply wants to grab a ref to the exclusive fence from a reservation object to store in the incoming drm_plane_state, without doing the whole RCU dance. Since each driver will need to do this, lets make a helper. v2: rename to _rcu instead of _unlocked to be more consistent Signed-off-by:

Rob Clark <robdclark@gmail.com> Acked-by:

Sumit Semwal <sumit.semwal@linaro.org>

include/linux/reservation.h

+18 −0

Original line number	Diff line number	Diff line
		@@ -120,6 +120,24 @@ reservation_object_get_excl(struct reservation_object *obj)
		reservation_object_held(obj));
		}

		static inline struct fence *
		reservation_object_get_excl_rcu(struct reservation_object *obj)
		{
		struct fence *fence;
		unsigned seq;
		retry:
		seq = read_seqcount_begin(&obj->seq);
		rcu_read_lock();
		fence = rcu_dereference(obj->fence_excl);
		if (read_seqcount_retry(&obj->seq, seq)) {
		rcu_read_unlock();
		goto retry;
		}
		fence = fence_get(fence);
		rcu_read_unlock();
		return fence;
		}

		int reservation_object_reserve_shared(struct reservation_object *obj);
		void reservation_object_add_shared_fence(struct reservation_object *obj,
		struct fence *fence);

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