X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=lib%2Flibrte_ring%2Frte_ring_c11_mem.h;h=0fb73a33717307c781da38b5a0e8797cabbed141;hb=refs%2Ftags%2Fupstream%2F18.11-rc3;hp=7bc74a4cb081eba8268391b786b95922a87ecf40;hpb=88fab00d4402af240c1b7cc2566133aece115488;p=deb_dpdk.git

diff --git a/lib/librte_ring/rte_ring_c11_mem.h b/lib/librte_ring/rte_ring_c11_mem.h
index 7bc74a4c..0fb73a33 100644
--- a/lib/librte_ring/rte_ring_c11_mem.h
+++ b/lib/librte_ring/rte_ring_c11_mem.h
@@ -61,11 +61,14 @@ __rte_ring_move_prod_head(struct rte_ring *r, unsigned int is_sp,
 	unsigned int max = n;
 	int success;
 
-	*old_head = __atomic_load_n(&r->prod.head, __ATOMIC_ACQUIRE);
+	*old_head = __atomic_load_n(&r->prod.head, __ATOMIC_RELAXED);
 	do {
 		/* Reset n to the initial burst count */
 		n = max;
 
+		/* Ensure the head is read before tail */
+		__atomic_thread_fence(__ATOMIC_ACQUIRE);
+
 		/* load-acquire synchronize with store-release of ht->tail
 		 * in update_tail.
 		 */
@@ -94,7 +97,7 @@ __rte_ring_move_prod_head(struct rte_ring *r, unsigned int is_sp,
 			/* on failure, *old_head is updated */
 			success = __atomic_compare_exchange_n(&r->prod.head,
 					old_head, *new_head,
-					0, __ATOMIC_ACQUIRE,
+					0, __ATOMIC_RELAXED,
 					__ATOMIC_RELAXED);
 	} while (unlikely(success == 0));
 	return n;
@@ -134,11 +137,14 @@ __rte_ring_move_cons_head(struct rte_ring *r, int is_sc,
 	int success;
 
 	/* move cons.head atomically */
-	*old_head = __atomic_load_n(&r->cons.head, __ATOMIC_ACQUIRE);
+	*old_head = __atomic_load_n(&r->cons.head, __ATOMIC_RELAXED);
 	do {
 		/* Restore n as it may change every loop */
 		n = max;
 
+		/* Ensure the head is read before tail */
+		__atomic_thread_fence(__ATOMIC_ACQUIRE);
+
 		/* this load-acquire synchronize with store-release of ht->tail
 		 * in update_tail.
 		 */
@@ -166,7 +172,7 @@ __rte_ring_move_cons_head(struct rte_ring *r, int is_sc,
 			/* on failure, *old_head will be updated */
 			success = __atomic_compare_exchange_n(&r->cons.head,
 							old_head, *new_head,
-							0, __ATOMIC_ACQUIRE,
+							0, __ATOMIC_RELAXED,
 							__ATOMIC_RELAXED);
 	} while (unlikely(success == 0));
 	return n;