[PATCH] dma-buf/reservation: Wrap ww_mutex_trylock

[Chris Wilson]

In a similar fashion to reservation_object_lock() and
reservation_object_unlock(), ww_mutex_trylock is also useful and so is
worth wrapping for consistency.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal at linaro.org>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 include/linux/reservation.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/include/linux/reservation.h b/include/linux/reservation.h
index 24da961b085d..28d544364e52 100644
--- a/include/linux/reservation.h
+++ b/include/linux/reservation.h
@@ -151,6 +151,26 @@ reservation_object_lock(struct reservation_object *obj,
 }
 
 /**
+ * reservation_object_trylock - trylock the reservation object
+ * @obj: the reservation object
+ *
+ * Tries to lock the reservation object for exclusive access and modification.
+ * Note, that the lock is only against other writers, readers will run
+ * concurrently with a writer under RCU. The seqlock is used to notify readers
+ * if they overlap with a writer.
+ *
+ * Also note that since no context is provided, no deadlock protection is
+ * possible.
+ *
+ * Returns true if the lock was acquired, false otherwise.
+ */
+static inline bool
+reservation_object_trylock(struct reservation_object *obj)
+{
+	return ww_mutex_trylock(&obj->lock);
+}
+
+/**
  * reservation_object_unlock - unlock the reservation object
  * @obj: the reservation object
  *
-- 
2.11.0