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

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.  This also avoids the need
to use supports_time64() (which breaks the usage case of live migration
like CRIU or similar).

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, 15 insertions, 25 deletions

diff --git a/sysdeps/unix/sysv/linux/ppoll.c b/sysdeps/unix/sysv/linux/ppoll.c
index 624f14f517..8ca133b1fa 100644
--- a/sysdeps/unix/sysv/linux/ppoll.c
+++ b/sysdeps/unix/sysv/linux/ppoll.c
@@ -21,9 +21,6 @@
 #include <time.h>
 #include <sys/poll.h>
 #include <sysdep-cancel.h>
-#include <kernel-features.h>
-#include <time64-support.h>
-
 
 int
 __ppoll64 (struct pollfd *fds, nfds_t nfds, const struct __timespec64 *timeout,
@@ -38,40 +35,33 @@ __ppoll64 (struct pollfd *fds, nfds_t nfds, const struct __timespec64 *timeout,
       timeout = &tval;
     }
 
-  int ret;
-
-  if (supports_time64 ())
-    {
 #ifndef __NR_ppoll_time64
 # define __NR_ppoll_time64 __NR_ppoll
 #endif
+
+#ifdef __ASSUME_TIME64_SYSCALLS
+  return SYSCALL_CANCEL (ppoll_time64, fds, nfds, timeout, sigmask,
+			 __NSIG_BYTES);
+#else
+  int ret;
+  bool need_time64 = timeout != NULL && !in_time_t_range (timeout->tv_sec);
+  if (need_time64)
+    {
       ret = SYSCALL_CANCEL (ppoll_time64, fds, nfds, timeout, sigmask,
 			    __NSIG_BYTES);
-
       if (ret == 0 || errno != ENOSYS)
 	return ret;
-
-      mark_time64_unsupported ();
+      __set_errno (EOVERFLOW);
+      return -1;
     }
 
-#ifndef __ASSUME_TIME64_SYSCALLS
   struct timespec ts32;
-  if (timeout)
-    {
-      if (! in_time_t_range (timeout->tv_sec))
-        {
-          __set_errno (EOVERFLOW);
-          return -1;
-        }
-
-      ts32 = valid_timespec64_to_timespec (*timeout);
-    }
+  if (timeout != NULL)
+    ts32 = valid_timespec64_to_timespec (*timeout);
 
-  ret = SYSCALL_CANCEL (ppoll, fds, nfds, timeout ? &ts32 : NULL, sigmask,
-			__NSIG_BYTES);
+  return SYSCALL_CANCEL (ppoll, fds, nfds, timeout ? &ts32 : NULL, sigmask,
+			 __NSIG_BYTES);
 #endif
-
-  return ret;
 }
 
 #if __TIMESIZE != 64