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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-06-15 21:00:50 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-06-22 12:09:52 -0300
commit4c3df0eba5e8fe98f0de917ade9b2ebba6951c5f (patch)
tree137a7ae34464f27fa19029863d4f6f06860e3150 /include
parent91cf411ad3ef10bd18ec053854fcb919be4f6789 (diff)
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linux: Only use 64-bit syscall if required for select
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).

It also fixes an issue on 32-bit select call for !__ASSUME_PSELECT
(microblase with older kernels only) where the expected timeout
is a 'struct timeval' instead of 'struct timespec'.

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>
Diffstat (limited to 'include')
-rw-r--r--include/sys/select.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/sys/select.h b/include/sys/select.h
index ec073deeba..a8961afbed 100644
--- a/include/sys/select.h
+++ b/include/sys/select.h
@@ -21,6 +21,11 @@ extern int __pselect32 (int __nfds, fd_set *__readfds,
 			const struct __timespec64 *__timeout,
 			const __sigset_t *__sigmask)
   attribute_hidden;
+extern int __select32 (int __nfds, fd_set *__readfds,
+		       fd_set *__writefds, fd_set *__exceptfds,
+		       const struct __timespec64 *ts64,
+		       struct __timeval64 *timeout)
+  attribute_hidden;
 
 extern int __select64 (int __nfds, fd_set *__readfds,
 		       fd_set *__writefds, fd_set *__exceptfds,