qemu_futex_timedwait() is equivalent to qemu_futex_wait(), except it has
an absolute timeout.

Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
---
 include/qemu/futex.h | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/include/qemu/futex.h b/include/qemu/futex.h
index 607613eec835..5b48f79bf329 100644
--- a/include/qemu/futex.h
+++ b/include/qemu/futex.h
@@ -24,13 +24,19 @@
 #ifndef QEMU_FUTEX_H
 #define QEMU_FUTEX_H
 
+#include "qemu/timer.h"
 #define HAVE_FUTEX
 
 #ifdef CONFIG_LINUX
 #include <sys/syscall.h>
 #include <linux/futex.h>
+#include <linux/time_types.h>
 
+#ifdef __NR_futex_time64
+#define qemu_futex(...)              syscall(__NR_futex_time64, __VA_ARGS__)
+#else
 #define qemu_futex(...)              syscall(__NR_futex, __VA_ARGS__)
+#endif
 
 static inline void qemu_futex_wake_all(void *f)
 {
@@ -42,18 +48,28 @@ static inline void qemu_futex_wake_single(void *f)
     qemu_futex(f, FUTEX_WAKE, 1, NULL, NULL, 0);
 }
 
-static inline void qemu_futex_wait(void *f, unsigned val)
+static inline bool qemu_futex_timedwait(void *f, unsigned val, int64_t ns)
 {
-    while (qemu_futex(f, FUTEX_WAIT, (int) val, NULL, NULL, 0)) {
+    struct __kernel_timespec ts;
+    uint32_t bitset = FUTEX_BITSET_MATCH_ANY;
+
+    ts.tv_sec = ns / NANOSECONDS_PER_SECOND;
+    ts.tv_nsec = ns % NANOSECONDS_PER_SECOND;
+
+    while (qemu_futex(f, FUTEX_WAIT_BITSET, (int) val, &ts, NULL, bitset)) {
         switch (errno) {
         case EWOULDBLOCK:
-            return;
+            return true;
         case EINTR:
             break; /* get out of switch and retry */
+        case ETIMEDOUT:
+            return false;
         default:
             abort();
         }
     }
+
+    return true;
 }
 #elif defined(CONFIG_WIN32)
 #include <synchapi.h>
@@ -68,12 +84,20 @@ static inline void qemu_futex_wake_single(void *f)
     WakeByAddressSingle(f);
 }
 
-static inline void qemu_futex_wait(void *f, unsigned val)
+static inline bool qemu_futex_timedwait(void *f, unsigned val, int64_t ns)
 {
-    WaitOnAddress(f, &val, sizeof(val), INFINITE);
+    DWORD duration = MIN((ns - get_clock()) / SCALE_MS, INFINITE);
+    return WaitOnAddress(f, &val, sizeof(val), duration);
 }
 #else
 #undef HAVE_FUTEX
 #endif
 
+#ifdef HAVE_FUTEX
+static inline void qemu_futex_wait(void *f, unsigned val)
+{
+    qemu_futex_timedwait(f, val, INT64_MAX);
+}
+#endif
+
 #endif /* QEMU_FUTEX_H */

-- 
2.52.0