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Commit 824815c4 authored by Rob Clark's avatar Rob Clark
Browse files

reservation: add reservation_object_get_excl_rcu() 



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: default avatarRob Clark <robdclark@gmail.com>
Acked-by: default avatarSumit Semwal <sumit.semwal@linaro.org>
parent feb46f02

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);