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

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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>
This commit is contained in:
Adhemerval Zanella 2021-06-15 22:43:51 -03:00
parent 4b6551902e
commit eef7913c2f
3 changed files with 56 additions and 28 deletions
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53
sysdeps/unix/sysv/linux/semtimedop.c
View File

@ -21,44 +21,51 @@
#include <sysdep.h>
#include <errno.h>
static int
semtimedop_syscall (int semid, struct sembuf *sops, size_t nsops,
const struct __timespec64 *timeout)
{
#ifdef __NR_semtimedop_time64
return INLINE_SYSCALL_CALL (semtimedop_time64, semid, sops, nsops, timeout);
#elif defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS && defined __NR_semtimedop
return INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, timeout);
#else
return INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,
SEMTIMEDOP_IPC_ARGS (nsops, sops, timeout));
#endif
}
/* Perform user-defined atomical operation of array of semaphores. */
int
__semtimedop64 (int semid, struct sembuf *sops, size_t nsops,
const struct __timespec64 *timeout)
{
int r;
#if defined __NR_semtimedop_time64
r = INLINE_SYSCALL_CALL (semtimedop_time64, semid, sops, nsops, timeout);
#elif defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS && defined __NR_semtimedop
r = INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, timeout);
#ifdef __ASSUME_TIME64_SYSCALLS
return semtimedop_syscall (semid, sops, nsops, timeout);
#else
r = INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,
SEMTIMEDOP_IPC_ARGS (nsops, sops, timeout));
#endif
#ifndef __ASSUME_TIME64_SYSCALLS
if (r == 0 || errno != ENOSYS)
return r;
bool need_time64 = timeout != NULL && !in_time_t_range (timeout->tv_sec);
if (need_time64)
{
int r = semtimedop_syscall (semid, sops, nsops, timeout);
if (r == 0 || errno != ENOSYS)
return r;
__set_errno (EOVERFLOW);
return -1;
}
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;
}
# if defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS
r = INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, pts32);
# ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
return INLINE_SYSCALL_CALL (semtimedop, semid, sops, nsops, pts32);
# else
r = INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,
SEMTIMEDOP_IPC_ARGS (nsops, sops, pts32));
return INLINE_SYSCALL_CALL (ipc, IPCOP_semtimedop, semid,
SEMTIMEDOP_IPC_ARGS (nsops, sops, pts32));
# endif
#endif /* __ASSUME_TIME64_SYSCALLS */
return r;
#endif
}
#if __TIMESIZE != 64
libc_hidden_def (__semtimedop64)

9
sysvipc/Makefile
View File

@ -38,3 +38,12 @@ include ../Rules
CFLAGS-msgrcv.c += -fexceptions -fasynchronous-unwind-tables
CFLAGS-msgsnd.c += -fexceptions -fasynchronous-unwind-tables
ifeq (yes,$(build-shared))
librt = $(common-objpfx)rt/librt.so
else
librt = $(common-objpfx)rt/librt.a
endif
$(objpfx)test-sysvsem: $(librt)
$(objpfx)test-sysvsem-time64: $(librt)

22
sysvipc/test-sysvsem.c
View File

@ -16,6 +16,7 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <intprops.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
@ -30,6 +31,8 @@
#include <support/support.h>
#include <support/check.h>
#include <support/temp_file.h>
#include <support/xtime.h>
#include <support/xsignal.h>
/* These are for the temporary file we generate. */
static char *name;
@ -112,11 +115,20 @@ do_test (void)
#ifdef _GNU_SOURCE
/* Set a time for half a second. The semaphore operation should timeout
with EAGAIN. */
struct timespec ts = { 0 /* sec */, 500000000 /* nsec */ };
if (semtimedop (semid, &sb2, 1, &ts) != -1
|| (errno != EAGAIN && errno != ENOSYS))
FAIL_EXIT1 ("semtimedop succeed or returned errno != {EAGAIN,ENOSYS} "
"(errno=%i)", errno);
{
struct timespec ts = { 0 /* sec */, 500000000 /* nsec */ };
if (semtimedop (semid, &sb2, 1, &ts) != -1
|| (errno != EAGAIN && errno != ENOSYS))
FAIL_EXIT1 ("semtimedop succeed or returned errno != {EAGAIN,ENOSYS} "
"(errno=%i)", errno);
}
{
support_create_timer (0, 100000000, false, NULL);
struct timespec ts = { TYPE_MAXIMUM (time_t), 0 };
TEST_COMPARE (semtimedop (semid, &sb2, 1, &ts), -1);
TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
}
#endif
/* Finally free up the semnaphore resource. */