X-Git-Url: https://git.lttng.org/?p=urcu.git;a=blobdiff_plain;f=urcu.c;h=5ffeb79553b6374f0fb1a607b3862ed78dda63e2;hp=1429f6dfbbd3f392b307a9139931bf24eeebd67a;hb=64f469e628fe45059f091f2808188fb52fa109c9;hpb=731ccb963c80afd067e20acee2f9bd7cb4875ffb

diff --git a/urcu.c b/urcu.c
index 1429f6d..5ffeb79 100644
--- a/urcu.c
+++ b/urcu.c
@@ -26,6 +26,7 @@
 #define _BSD_SOURCE
 #define _GNU_SOURCE
 #define _LGPL_SOURCE
+#define _DEFAULT_SOURCE
 #include <stdio.h>
 #include <pthread.h>
 #include <signal.h>
@@ -76,9 +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;
@@ -148,7 +150,7 @@ static void mutex_lock(pthread_mutex_t *mutex)
 			_CMM_STORE_SHARED(URCU_TLS(rcu_reader).need_mb, 0);
 			cmm_smp_mb();
 		}
-		poll(NULL,0,10);
+		(void) poll(NULL, 0, 10);
 	}
 #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */
 }
@@ -166,7 +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();
 }
@@ -216,7 +218,7 @@ static void force_mb_all_readers(void)
 	cds_list_for_each_entry(index, &registry, node) {
 		while (CMM_LOAD_SHARED(index->need_mb)) {
 			pthread_kill(index->tid, SIGRCU);
-			poll(NULL, 0, 1);
+			(void) poll(NULL, 0, 1);
 		}
 	}
 	cmm_smp_mb();	/* read ->need_mb before ending the barrier */
@@ -235,9 +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);
+		}
+	}
 }
 
 /*
@@ -500,11 +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