linux: Only use 64-bit syscall if required for sigtimedwait

For !__ASSUME_TIME64_SYSCALLS there is no need to issue a 64-bit syscall
if the provided timeout fits in a 32-bit one.  The 64-bit usage should
be rare since the timeout is a relative one.

Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
(with and without --enable-kernel=5.1) and on x86_64-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>

1 files changed, 16 insertions, 9 deletions

diff --git a/sysdeps/unix/sysv/linux/sigtimedwait.c b/sysdeps/unix/sysv/linux/sigtimedwait.c
index 25ed0adb0d..607381a0a7 100644
--- a/sysdeps/unix/sysv/linux/sigtimedwait.c
+++ b/sysdeps/unix/sysv/linux/sigtimedwait.c
@@ -25,20 +25,27 @@ __sigtimedwait64 (const sigset_t *set, siginfo_t *info,
 #ifndef __NR_rt_sigtimedwait_time64
 # define __NR_rt_sigtimedwait_time64 __NR_rt_sigtimedwait
 #endif
-  int result = SYSCALL_CANCEL (rt_sigtimedwait_time64, set, info, timeout,
-			       __NSIG_BYTES);
 
-#ifndef __ASSUME_TIME64_SYSCALLS
-  if (result != 0 && errno == ENOSYS)
+  int result;
+#ifdef __ASSUME_TIME64_SYSCALLS
+  result = SYSCALL_CANCEL (rt_sigtimedwait_time64, set, info, timeout,
+			   __NSIG_BYTES);
+#else
+  bool need_time64 = timeout != NULL && !in_time_t_range (timeout->tv_sec);
+  if (need_time64)
+    {
+      result = SYSCALL_CANCEL (rt_sigtimedwait_time64, set, info, timeout,
+			       __NSIG_BYTES);
+      if (result == 0 || errno != ENOSYS)
+	return result;
+      __set_errno (EOVERFLOW);
+      return -1;
+    }
+  else
     {
       struct timespec ts32, *pts32 = NULL;
       if (timeout != NULL)
 	{
-	  if (! in_time_t_range (timeout->tv_sec))
-	    {
-	      __set_errno (EINVAL);
-	      return -1;
-	    }
 	  ts32 = valid_timespec64_to_timespec (*timeout);
 	  pts32 = &ts32;
 	}