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

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 22:56:12 -03:00
parent eef7913c2f
commit 2c0982eb93
3 changed files with 48 additions and 13 deletions
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2
sysdeps/unix/sysv/linux/Makefile
View File

@ -145,6 +145,8 @@ endif
$(objpfx)tst-ppoll: $(librt)
$(objpfx)tst-ppoll-time64: $(librt)
$(objpfx)tst-timerfd: $(librt)
$(objpfx)tst-timerfd-time64: $(librt)
# Generate the list of SYS_* macros for the system calls (__NR_*
# macros). The file syscall-names.list contains all possible system

25
sysdeps/unix/sysv/linux/timerfd_settime.c
View File

@ -29,31 +29,34 @@ __timerfd_settime64 (int fd, int flags, const struct __itimerspec64 *value,
#ifndef __NR_timerfd_settime64
# define __NR_timerfd_settime64 __NR_timerfd_settime
#endif
int ret = INLINE_SYSCALL_CALL (timerfd_settime64, fd, flags, value, ovalue);
#ifndef __ASSUME_TIME64_SYSCALLS
if (ret == 0 || errno != ENOSYS)
return ret;
if (! in_time_t_range ((value->it_value).tv_sec)
|| ! in_time_t_range ((value->it_interval).tv_sec))
#ifdef __ASSUME_TIME64_SYSCALLS
return INLINE_SYSCALL_CALL (timerfd_settime64, fd, flags, value, ovalue);
#else
bool need_time64 = !in_time_t_range (value->it_value.tv_sec)
|| !in_time_t_range (value->it_interval.tv_sec);
if (need_time64)
{
int r = INLINE_SYSCALL_CALL (timerfd_settime64, fd, flags, value,
ovalue);
if (r == 0 || errno != ENOSYS)
return r;
__set_errno (EOVERFLOW);
return -1;
return r;
}
struct itimerspec its32, oits32;
its32.it_interval = valid_timespec64_to_timespec (value->it_interval);
its32.it_value = valid_timespec64_to_timespec (value->it_value);
ret = INLINE_SYSCALL_CALL (timerfd_settime, fd, flags,
&its32, ovalue ? &oits32 : NULL);
int ret = INLINE_SYSCALL_CALL (timerfd_settime, fd, flags,
&its32, ovalue != NULL ? &oits32 : NULL);
if (ret == 0 && ovalue != NULL)
{
ovalue->it_interval = valid_timespec_to_timespec64 (oits32.it_interval);
ovalue->it_value = valid_timespec_to_timespec64 (oits32.it_value);
}
#endif
return ret;
#endif
}
#if __TIMESIZE != 64

34
sysdeps/unix/sysv/linux/tst-timerfd.c
View File

@ -16,15 +16,18 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <intprops.h>
#include <time.h>
#include <support/check.h>
#include <support/support.h>
#include <support/xunistd.h>
#include <support/timespec.h>
#include <sys/time.h>
#include <sys/timerfd.h>
static int
do_test (void)
static void
timerfd_test (void)
{
struct itimerspec settings = { { 0, 0 }, { 2, 0 } };
struct itimerspec val;
@ -52,6 +55,33 @@ do_test (void)
/* Check difference between timerfd_gettime calls. */
TEST_COMPARE (support_timespec_check_in_range
((struct timespec) { 1, 0 }, val.it_value, 0.9, 1.0), 1);
xclose (fd);
}
static void
timerfd_large_timeout (void)
{
int fd = timerfd_create (CLOCK_REALTIME, 0);
TEST_VERIFY (fd != -1);
support_create_timer (0, 100000000, false, NULL);
struct itimerspec it = { { 0, 0 }, { TYPE_MAXIMUM (time_t), 0 } };
int r = timerfd_settime (fd, 0, &it, NULL);
if (r == 0)
{
uint64_t buf;
TEST_COMPARE (read (fd, &buf, sizeof (buf)), -1);
TEST_VERIFY (errno == EINTR);
}
else
TEST_COMPARE (errno, EOVERFLOW);
}
static int
do_test (void)
{
timerfd_test ();
timerfd_large_timeout ();
return 0;
}