diff mbox series

[14/18] linux: Only use 64-bit syscall if required for mq_timedsend

Message ID 20210617115104.1359598-15-adhemerval.zanella@linaro.org
State Committed
Headers
Series More y2038 fixes |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Adhemerval Zanella June 17, 2021, 11:51 a.m. UTC 
  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/tst-mqueue10.c                      | 10 ++++++++
 sysdeps/unix/sysv/linux/mq_timedsend.c | 35 ++++++++++++++------------
 2 files changed, 29 insertions(+), 16 deletions(-)

Comments

Lukasz Majewski June 21, 2021, 7:44 a.m. UTC | #1 
On Thu, 17 Jun 2021 08:51:00 -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/tst-mqueue10.c                      | 10 ++++++++
>  sysdeps/unix/sysv/linux/mq_timedsend.c | 35
> ++++++++++++++------------ 2 files changed, 29 insertions(+), 16
> deletions(-)
> 
> diff --git a/rt/tst-mqueue10.c b/rt/tst-mqueue10.c
> index 7fb53a1cae..18795808e0 100644
> --- a/rt/tst-mqueue10.c
> +++ b/rt/tst-mqueue10.c
> @@ -54,6 +54,16 @@ do_test (void)
>      support_delete_timer (timer);
>    }
>  
> +  {
> +    timer_t timer = support_create_timer (0, 100000000, false, NULL);
> +    /* Fill the internal buffer first.  */
> +    TEST_COMPARE (mq_timedsend (q, msg, sizeof (msg), 0,
> +				&(struct timespec) { 0, 0 }), 0);
> +    TEST_COMPARE (mq_timedsend (q, msg, sizeof (msg), 0, &ts), -1);
> +    TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
> +    support_delete_timer (timer);
> +  }
> +
>    mq_unlink (name);
>  
>    return 0;
> diff --git a/sysdeps/unix/sysv/linux/mq_timedsend.c
> b/sysdeps/unix/sysv/linux/mq_timedsend.c index 5f14ecb0bf..8fa8c010ad
> 100644 --- a/sysdeps/unix/sysv/linux/mq_timedsend.c
> +++ b/sysdeps/unix/sysv/linux/mq_timedsend.c
> @@ -29,30 +29,33 @@ __mq_timedsend_time64 (mqd_t mqdes, const char
> *msg_ptr, size_t msg_len, # ifndef __NR_mq_timedsend_time64
>  #  define __NR_mq_timedsend_time64 __NR_mq_timedsend
>  # endif
> -  int ret = SYSCALL_CANCEL (mq_timedsend_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_timedsend_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_timedsend_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_timedsend, mqdes, msg_ptr, msg_len,
> msg_prio,
> -			abs_timeout != NULL ? &ts32 : NULL);
> +  return SYSCALL_CANCEL (mq_timedsend, 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
diff mbox series

Patch

diff --git a/rt/tst-mqueue10.c b/rt/tst-mqueue10.c
index 7fb53a1cae..18795808e0 100644
--- a/rt/tst-mqueue10.c
+++ b/rt/tst-mqueue10.c
@@ -54,6 +54,16 @@  do_test (void)
     support_delete_timer (timer);
   }
 
+  {
+    timer_t timer = support_create_timer (0, 100000000, false, NULL);
+    /* Fill the internal buffer first.  */
+    TEST_COMPARE (mq_timedsend (q, msg, sizeof (msg), 0,
+				&(struct timespec) { 0, 0 }), 0);
+    TEST_COMPARE (mq_timedsend (q, msg, sizeof (msg), 0, &ts), -1);
+    TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
+    support_delete_timer (timer);
+  }
+
   mq_unlink (name);
 
   return 0;
diff --git a/sysdeps/unix/sysv/linux/mq_timedsend.c b/sysdeps/unix/sysv/linux/mq_timedsend.c
index 5f14ecb0bf..8fa8c010ad 100644
--- a/sysdeps/unix/sysv/linux/mq_timedsend.c
+++ b/sysdeps/unix/sysv/linux/mq_timedsend.c
@@ -29,30 +29,33 @@  __mq_timedsend_time64 (mqd_t mqdes, const char *msg_ptr, size_t msg_len,
 # ifndef __NR_mq_timedsend_time64
 #  define __NR_mq_timedsend_time64 __NR_mq_timedsend
 # endif
-  int ret = SYSCALL_CANCEL (mq_timedsend_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_timedsend_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_timedsend_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_timedsend, mqdes, msg_ptr, msg_len, msg_prio,
-			abs_timeout != NULL ? &ts32 : NULL);
+  return SYSCALL_CANCEL (mq_timedsend, mqdes, msg_ptr, msg_len, msg_prio,
+			 pts32);
 #endif
-
-  return ret;
 }
 
 #if __TIMESIZE != 64