[PATCH 13/18] linux: Only use 64-bit syscall if required for mq_timedreceive
Lukasz Majewski
lukma@denx.de
Mon Jun 21 07:44:17 GMT 2021
On Thu, 17 Jun 2021 08:50:59 -0300
Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:
> 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.
> ---
> rt/Makefile | 4 +-
> rt/tst-mqueue10-time64.c | 1 +
> rt/tst-mqueue10.c | 62
> +++++++++++++++++++++++ sysdeps/unix/sysv/linux/mq_timedreceive.c |
> 35 +++++++------ 4 files changed, 85 insertions(+), 17 deletions(-)
> create mode 100644 rt/tst-mqueue10-time64.c
> create mode 100644 rt/tst-mqueue10.c
>
> diff --git a/rt/Makefile b/rt/Makefile
> index 797f2da51e..3382c7a1d2 100644
> --- a/rt/Makefile
> +++ b/rt/Makefile
> @@ -48,7 +48,8 @@ tests := tst-shm tst-timer tst-timer2 \
> tst-mqueue5 tst-mqueue6 tst-mqueue7 tst-mqueue8 tst-mqueue9
> \ tst-timer3 tst-timer4 tst-timer5 \
> tst-cpuclock2 tst-cputimer1 tst-cputimer2 tst-cputimer3 \
> - tst-shm-cancel
> + tst-shm-cancel \
> + tst-mqueue10
> tests-internal := tst-timer-sigmask
>
> tests-time64 := \
> @@ -58,6 +59,7 @@ tests-time64 := \
> tst-mqueue2-time64 \
> tst-mqueue4-time64 \
> tst-mqueue8-time64 \
> + tst-mqueue10-time64 \
> tst-timer4-time64
>
> extra-libs := librt
> diff --git a/rt/tst-mqueue10-time64.c b/rt/tst-mqueue10-time64.c
> new file mode 100644
> index 0000000000..2c8a4ae372
> --- /dev/null
> +++ b/rt/tst-mqueue10-time64.c
> @@ -0,0 +1 @@
> +#include "tst-mqueue10.c"
> diff --git a/rt/tst-mqueue10.c b/rt/tst-mqueue10.c
> new file mode 100644
> index 0000000000..7fb53a1cae
> --- /dev/null
> +++ b/rt/tst-mqueue10.c
> @@ -0,0 +1,62 @@
> +/* Check for large timeout with mq_timedsend and mq_timedreceive.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be
> useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <errno.h>
> +#include <intprops.h>
> +#include <mqueue.h>
> +#include <stdio.h>
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <support/temp_file.h>
> +#include <unistd.h>
> +
> +static char name[sizeof "/tst-mqueue2-" + INT_BUFSIZE_BOUND (pid_t)];
> +
> +static void
> +do_cleanup (void)
> +{
> + mq_unlink (name);
> +}
> +#define CLEANUP_HANDLER do_cleanup
> +
> +static int
> +do_test (void)
> +{
> + snprintf (name, sizeof (name), "/tst-mqueue2-%u", getpid ());
> +
> + char msg[8] = { 0x55 };
> +
> + struct mq_attr attr = { .mq_maxmsg = 1, .mq_msgsize = sizeof (msg)
> };
> + mqd_t q = mq_open (name, O_CREAT | O_EXCL | O_RDWR, 0600, &attr);
> + TEST_VERIFY_EXIT (q != (mqd_t) -1);
> +
> + struct timespec ts = { TYPE_MAXIMUM (time_t), 0 };
> +
> + {
> + timer_t timer = support_create_timer (0, 100000000, false, NULL);
> + TEST_COMPARE (mq_timedreceive (q, msg, sizeof (msg), NULL, &ts),
> -1);
> + TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
> + support_delete_timer (timer);
> + }
> +
> + mq_unlink (name);
> +
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
> diff --git a/sysdeps/unix/sysv/linux/mq_timedreceive.c
> b/sysdeps/unix/sysv/linux/mq_timedreceive.c index
> eb948ccc18..8776977daf 100644 ---
> a/sysdeps/unix/sysv/linux/mq_timedreceive.c +++
> b/sysdeps/unix/sysv/linux/mq_timedreceive.c @@ -29,30 +29,33 @@
> __mq_timedreceive_time64 (mqd_t mqdes, char *__restrict msg_ptr,
> size_t msg_len, #ifndef __NR_mq_timedreceive_time64 # define
> __NR_mq_timedreceive_time64 __NR_mq_timedreceive #endif
> - int ret = SYSCALL_CANCEL (mq_timedreceive_time64, mqdes, msg_ptr,
> msg_len,
> - msg_prio, abs_timeout);
>
> -#ifndef __ASSUME_TIME64_SYSCALLS
> - if (ret == 0 || errno != ENOSYS)
> - return ret;
> +#ifdef __ASSUME_TIME64_SYSCALLS
> + return SYSCALL_CANCEL (mq_timedreceive_time64, mqdes, msg_ptr,
> msg_len,
> + msg_prio, abs_timeout);
> +#else
> + bool is32bit = abs_timeout != NULL
> + ? in_time_t_range (abs_timeout->tv_sec) : true;
> + if (!is32bit)
> + {
> + int r = SYSCALL_CANCEL (mq_timedreceive_time64, mqdes,
> msg_ptr, msg_len,
> + msg_prio, abs_timeout);
> + if (r == 0 || errno != ENOSYS)
> + return r;
> + __set_errno (EOVERFLOW);
> + return -1;
> + }
>
> - struct timespec ts32;
> + struct timespec ts32, *pts32 = NULL;
> if (abs_timeout != NULL)
> {
> - if (! in_time_t_range (abs_timeout->tv_sec))
> - {
> - __set_errno (EOVERFLOW);
> - return -1;
> - }
> -
> ts32 = valid_timespec64_to_timespec (*abs_timeout);
> + pts32 = &ts32;
> }
>
> - ret = SYSCALL_CANCEL (mq_timedreceive, mqdes, msg_ptr, msg_len,
> msg_prio,
> - abs_timeout != NULL ? &ts32 : NULL);
> + return SYSCALL_CANCEL (mq_timedreceive, mqdes, msg_ptr, msg_len,
> msg_prio,
> + pts32);
> #endif
> -
> - return ret;
> }
>
> #if __TIMESIZE != 64
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
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