X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=lib%2Flibrte_ring%2Frte_ring.h;h=eb45e41449b33a2e5292ca12c317e161da7cb4ab;hb=99c12dcca65d;hp=fb5a6263a1f9e9bb178518daac78fd0a75ffa248;hpb=4e32101f9b01827ed24bf26c53cc9aec7e8db231;p=dpdk.git

diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index fb5a6263a1..eb45e41449 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -431,6 +431,11 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
 	uint32_t mask = r->prod.mask;
 	int ret;
 
+	/* Avoid the unnecessary cmpset operation below, which is also
+	 * potentially harmful when n equals 0. */
+	if (n == 0)
+		return 0;
+
 	/* move prod.head atomically */
 	do {
 		/* Reset n to the initial burst count */
@@ -468,7 +473,7 @@ __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
 
 	/* write entries in ring */
 	ENQUEUE_PTRS();
-	rte_compiler_barrier();
+	rte_smp_wmb();
 
 	/* if we exceed the watermark */
 	if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
@@ -563,7 +568,7 @@ __rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
 
 	/* write entries in ring */
 	ENQUEUE_PTRS();
-	rte_compiler_barrier();
+	rte_smp_wmb();
 
 	/* if we exceed the watermark */
 	if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
@@ -618,6 +623,11 @@ __rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
 	unsigned i, rep = 0;
 	uint32_t mask = r->prod.mask;
 
+	/* Avoid the unnecessary cmpset operation below, which is also
+	 * potentially harmful when n equals 0. */
+	if (n == 0)
+		return 0;
+
 	/* move cons.head atomically */
 	do {
 		/* Restore n as it may change every loop */
@@ -654,7 +664,7 @@ __rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
 
 	/* copy in table */
 	DEQUEUE_PTRS();
-	rte_compiler_barrier();
+	rte_smp_rmb();
 
 	/*
 	 * If there are other dequeues in progress that preceded us,
@@ -738,7 +748,7 @@ __rte_ring_sc_do_dequeue(struct rte_ring *r, void **obj_table,
 
 	/* copy in table */
 	DEQUEUE_PTRS();
-	rte_compiler_barrier();
+	rte_smp_rmb();
 
 	__RING_STAT_ADD(r, deq_success, n);
 	r->cons.tail = cons_next;
@@ -1037,7 +1047,7 @@ rte_ring_full(const struct rte_ring *r)
 {
 	uint32_t prod_tail = r->prod.tail;
 	uint32_t cons_tail = r->cons.tail;
-	return (((cons_tail - prod_tail - 1) & r->prod.mask) == 0);
+	return ((cons_tail - prod_tail - 1) & r->prod.mask) == 0;
 }
 
 /**
@@ -1070,7 +1080,7 @@ rte_ring_count(const struct rte_ring *r)
 {
 	uint32_t prod_tail = r->prod.tail;
 	uint32_t cons_tail = r->cons.tail;
-	return ((prod_tail - cons_tail) & r->prod.mask);
+	return (prod_tail - cons_tail) & r->prod.mask;
 }
 
 /**
@@ -1086,7 +1096,7 @@ rte_ring_free_count(const struct rte_ring *r)
 {
 	uint32_t prod_tail = r->prod.tail;
 	uint32_t cons_tail = r->cons.tail;
-	return ((cons_tail - prod_tail - 1) & r->prod.mask);
+	return (cons_tail - prod_tail - 1) & r->prod.mask;
 }
 
 /**