Update following changes to sys_membarrier ABI

[urcu.git] / urcu.c

diff --git a/urcu.c b/urcu.c
index 94d1131e3dba6df7982a33def88f6ec3908c2bf2..5ffeb79553b6374f0fb1a607b3862ed78dda63e2 100644 (file)
--- a/urcu.c
+++ b/urcu.c
@@ -77,9 +77,10 @@
 # define membarrier(...)               -ENOSYS
 #endif
 
-#define MEMBARRIER_EXPEDITED           (1 << 0)
-#define MEMBARRIER_DELAYED             (1 << 1)
-#define MEMBARRIER_QUERY               (1 << 16)
+enum membarrier_cmd {
+       MEMBARRIER_CMD_QUERY = 0,
+       MEMBARRIER_CMD_SHARED = (1 << 0),
+};
 
 #ifdef RCU_MEMBARRIER
 static int init_done;
@@ -167,7 +168,7 @@ static void mutex_unlock(pthread_mutex_t *mutex)
 static void smp_mb_master(int group)
 {
        if (caa_likely(rcu_has_sys_membarrier))
-               (void) membarrier(MEMBARRIER_EXPEDITED);
+               (void) membarrier(MEMBARRIER_CMD_SHARED, 0);
        else
                cmm_smp_mb();
 }
@@ -236,9 +237,22 @@ static void wait_gp(void)
 {
        /* Read reader_gp before read futex */
        smp_mb_master(RCU_MB_GROUP);
-       if (uatomic_read(&rcu_gp.futex) == -1)
-               futex_async(&rcu_gp.futex, FUTEX_WAIT, -1,
-                     NULL, NULL, 0);
+       if (uatomic_read(&rcu_gp.futex) != -1)
+               return;
+       while (futex_async(&rcu_gp.futex, FUTEX_WAIT, -1,
+                       NULL, NULL, 0)) {
+               switch (errno) {
+               case EWOULDBLOCK:
+                       /* Value already changed. */
+                       return;
+               case EINTR:
+                       /* Retry if interrupted by signal. */
+                       break;  /* Get out of switch. */
+               default:
+                       /* Unexpected error. */
+                       urcu_die(errno);
+               }
+       }
 }
 
 /*
@@ -501,11 +515,15 @@ void rcu_unregister_thread(void)
 #ifdef RCU_MEMBARRIER
 void rcu_init(void)
 {
+       int ret;
+
        if (init_done)
                return;
        init_done = 1;
-       if (!membarrier(MEMBARRIER_EXPEDITED | MEMBARRIER_QUERY))
+       ret = membarrier(MEMBARRIER_CMD_QUERY, 0);
+       if (ret >= 0 && (ret & MEMBARRIER_CMD_SHARED)) {
                rcu_has_sys_membarrier = 1;
+       }
 }
 #endif