X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=urcu%2Ffutex.h;h=753df622005f8d4103010e9f324827e8f97f2b62;hb=941e44562b045e71cad5e7faa84998d0fc5e8b64;hp=4beb54a3d206f2d68e905dd25233f7e6819a529f;hpb=999991c6e4600c410181baea65bda9f406464872;p=userspace-rcu.git

diff --git a/urcu/futex.h b/urcu/futex.h
index 4beb54a..753df62 100644
--- a/urcu/futex.h
+++ b/urcu/futex.h
@@ -28,7 +28,7 @@
 
 #ifdef __cplusplus
 extern "C" {
-#endif 
+#endif
 
 #define FUTEX_WAIT		0
 #define FUTEX_WAKE		1
@@ -73,7 +73,16 @@ static inline int futex_noasync(int32_t *uaddr, int op, int32_t val,
 
 	ret = futex(uaddr, op, val, timeout, uaddr2, val3);
 	if (caa_unlikely(ret < 0 && errno == ENOSYS)) {
-		return compat_futex_noasync(uaddr, op, val, timeout,
+		/*
+		 * The fallback on ENOSYS is the async-safe version of
+		 * the compat futex implementation, because the
+		 * async-safe compat implementation allows being used
+		 * concurrently with calls to futex(). Indeed, sys_futex
+		 * FUTEX_WAIT, on some architectures (mips and parisc),
+		 * within a given process, spuriously return ENOSYS due
+		 * to signal restart bugs on some kernel versions.
+		 */
+		return compat_futex_async(uaddr, op, val, timeout,
 				uaddr2, val3);
 	}
 	return ret;
@@ -93,6 +102,25 @@ static inline int futex_async(int32_t *uaddr, int op, int32_t val,
 	return ret;
 }
 
+#elif defined(__CYGWIN__)
+
+/*
+ * The futex_noasync compat code uses a weak symbol to share state across
+ * different shared object which is not possible on Windows with the
+ * Portable Executable format. Use the async compat code for both cases.
+ */
+static inline int futex_noasync(int32_t *uaddr, int op, int32_t val,
+		const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
+{
+	return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3);
+}
+
+static inline int futex_async(int32_t *uaddr, int op, int32_t val,
+		const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
+{
+	return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3);
+}
+
 #else
 
 static inline int futex_noasync(int32_t *uaddr, int op, int32_t val,
@@ -109,7 +137,7 @@ static inline int futex_async(int32_t *uaddr, int op, int32_t val,
 
 #endif
 
-#ifdef __cplusplus 
+#ifdef __cplusplus
 }
 #endif