X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=lib%2Flibrte_eal%2Fcommon%2Finclude%2Fgeneric%2Frte_rwlock.h;h=da9bc3e9c0e2fd98d2a040f1daae91de14555b9d;hb=df3ff6be2b33faea3edf3c112b9bdc5b74d6f684;hp=5751a0e6d5b9fb6d5e2ce88f057cee570829aef9;hpb=1587d36e22d0cf0e037a104e1e851acefd6597f0;p=dpdk.git

diff --git a/lib/librte_eal/common/include/generic/rte_rwlock.h b/lib/librte_eal/common/include/generic/rte_rwlock.h
index 5751a0e6d5..da9bc3e9c0 100644
--- a/lib/librte_eal/common/include/generic/rte_rwlock.h
+++ b/lib/librte_eal/common/include/generic/rte_rwlock.h
@@ -64,17 +64,49 @@ rte_rwlock_read_lock(rte_rwlock_t *rwl)
 	int success = 0;
 
 	while (success == 0) {
-		x = rwl->cnt;
+		x = __atomic_load_n(&rwl->cnt, __ATOMIC_RELAXED);
 		/* write lock is held */
 		if (x < 0) {
 			rte_pause();
 			continue;
 		}
-		success = rte_atomic32_cmpset((volatile uint32_t *)&rwl->cnt,
-					      (uint32_t)x, (uint32_t)(x + 1));
+		success = __atomic_compare_exchange_n(&rwl->cnt, &x, x + 1, 1,
+					__ATOMIC_ACQUIRE, __ATOMIC_RELAXED);
 	}
 }
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * try to take a read lock.
+ *
+ * @param rwl
+ *   A pointer to a rwlock structure.
+ * @return
+ *   - zero if the lock is successfully taken
+ *   - -EBUSY if lock could not be acquired for reading because a
+ *     writer holds the lock
+ */
+__rte_experimental
+static inline int
+rte_rwlock_read_trylock(rte_rwlock_t *rwl)
+{
+	int32_t x;
+	int success = 0;
+
+	while (success == 0) {
+		x = __atomic_load_n(&rwl->cnt, __ATOMIC_RELAXED);
+		/* write lock is held */
+		if (x < 0)
+			return -EBUSY;
+		success = __atomic_compare_exchange_n(&rwl->cnt, &x, x + 1, 1,
+					__ATOMIC_ACQUIRE, __ATOMIC_RELAXED);
+	}
+
+	return 0;
+}
+
 /**
  * Release a read lock.
  *
@@ -84,7 +116,34 @@ rte_rwlock_read_lock(rte_rwlock_t *rwl)
 static inline void
 rte_rwlock_read_unlock(rte_rwlock_t *rwl)
 {
-	rte_atomic32_dec((rte_atomic32_t *)(intptr_t)&rwl->cnt);
+	__atomic_fetch_sub(&rwl->cnt, 1, __ATOMIC_RELEASE);
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * try to take a write lock.
+ *
+ * @param rwl
+ *   A pointer to a rwlock structure.
+ * @return
+ *   - zero if the lock is successfully taken
+ *   - -EBUSY if lock could not be acquired for writing because
+ *     it was already locked for reading or writing
+ */
+__rte_experimental
+static inline int
+rte_rwlock_write_trylock(rte_rwlock_t *rwl)
+{
+	int32_t x;
+
+	x = __atomic_load_n(&rwl->cnt, __ATOMIC_RELAXED);
+	if (x != 0 || __atomic_compare_exchange_n(&rwl->cnt, &x, -1, 1,
+			      __ATOMIC_ACQUIRE, __ATOMIC_RELAXED) == 0)
+		return -EBUSY;
+
+	return 0;
 }
 
 /**
@@ -100,14 +159,14 @@ rte_rwlock_write_lock(rte_rwlock_t *rwl)
 	int success = 0;
 
 	while (success == 0) {
-		x = rwl->cnt;
+		x = __atomic_load_n(&rwl->cnt, __ATOMIC_RELAXED);
 		/* a lock is held */
 		if (x != 0) {
 			rte_pause();
 			continue;
 		}
-		success = rte_atomic32_cmpset((volatile uint32_t *)&rwl->cnt,
-					      0, (uint32_t)-1);
+		success = __atomic_compare_exchange_n(&rwl->cnt, &x, -1, 1,
+					__ATOMIC_ACQUIRE, __ATOMIC_RELAXED);
 	}
 }
 
@@ -120,7 +179,7 @@ rte_rwlock_write_lock(rte_rwlock_t *rwl)
 static inline void
 rte_rwlock_write_unlock(rte_rwlock_t *rwl)
 {
-	rte_atomic32_inc((rte_atomic32_t *)(intptr_t)&rwl->cnt);
+	__atomic_store_n(&rwl->cnt, 0, __ATOMIC_RELEASE);
 }
 
 /**