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authorRob Clark <robdclark@gmail.com>2016-03-31 23:23:51 +0300
committerRob Clark <robdclark@gmail.com>2016-05-08 17:16:02 +0300
commit824815c4cd13e384ef5a4be725ec4b06e4ad2c2a (patch)
treeba1e68f32df845da41e8b8c9a0922713cca27111 /include/linux/reservation.h
parentfeb46f02c3fa70e6d3e5307cb105cc69c60a3fe3 (diff)
downloadlinux-824815c4cd13e384ef5a4be725ec4b06e4ad2c2a.tar.xz
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: Rob Clark <robdclark@gmail.com> Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Diffstat (limited to 'include/linux/reservation.h')
-rw-r--r--include/linux/reservation.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/reservation.h b/include/linux/reservation.h
index 5a0b64cf68b4..49d057655d62 100644
--- a/include/linux/reservation.h
+++ b/include/linux/reservation.h
@@ -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);