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

Message ID 20210617115104.1359598-15-adhemerval.zanella@linaro.org
State New
Headers show
Series
  • More y2038 fixes
Related show

Commit Message

DJ Delorie via Libc-alpha June 17, 2021, 11:51 a.m.
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(-)

-- 
2.30.2

Comments

Lukasz Majewski June 21, 2021, 7:44 a.m. | #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

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