X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Ffutex.h;h=0486ff6a1830f174d7471164a282507a6d1f756c;hp=13d2b1a0a9c73904563e2b9b46d40d19e3316686;hb=b2633d211b186cb201be327ded53ecf523ecf0bd;hpb=42dfe454abcd206bb2005261c6b79cb3d4f9ce29

diff --git a/urcu/futex.h b/urcu/futex.h
index 13d2b1a..0486ff6 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
@@ -57,7 +57,7 @@ extern int compat_futex_async(int32_t *uaddr, int op, int32_t val,
 #include <unistd.h>
 #include <errno.h>
 #include <urcu/compiler.h>
-#include <urcu/syscall-compat.h>
+#include <urcu/arch.h>
 
 static inline int futex(int32_t *uaddr, int op, int32_t val,
 		const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
@@ -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;
@@ -109,7 +118,7 @@ static inline int futex_async(int32_t *uaddr, int op, int32_t val,
 
 #endif
 
-#ifdef __cplusplus 
+#ifdef __cplusplus
 }
 #endif