X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=lib%2Flibrte_eal%2Finclude%2Fgeneric%2Frte_mcslock.h;h=d370bef17a4d64db296bda5a625bf4a7ef6309ba;hb=021b698eb56e48009d74d818bea5a9bdad4f54fa;hp=78b0df295e2d9a4341921695a1a83734f6be0224;hpb=f32fed83db8ba3f929d520bd370df612728a130b;p=dpdk.git

diff --git a/lib/librte_eal/include/generic/rte_mcslock.h b/lib/librte_eal/include/generic/rte_mcslock.h
index 78b0df295e..d370bef17a 100644
--- a/lib/librte_eal/include/generic/rte_mcslock.h
+++ b/lib/librte_eal/include/generic/rte_mcslock.h
@@ -64,7 +64,14 @@ rte_mcslock_lock(rte_mcslock_t **msl, rte_mcslock_t *me)
 		 */
 		return;
 	}
-	__atomic_store_n(&prev->next, me, __ATOMIC_RELAXED);
+	/* The store to me->next above should also complete before the node is
+	 * visible to predecessor thread releasing the lock. Hence, the store
+	 * prev->next also requires release semantics. Note that, for example,
+	 * on ARM, the release semantics in the exchange operation is not
+	 * strong as a release fence and is not sufficient to enforce the
+	 * desired order here.
+	 */
+	__atomic_store_n(&prev->next, me, __ATOMIC_RELEASE);
 
 	/* The while-load of me->locked should not move above the previous
 	 * store to prev->next. Otherwise it will cause a deadlock. Need a