Patchwork [4/7] nptl: pthread_rwlock: Move timeout validation into _full functions

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Submitter Mike Crowe
Date Feb. 27, 2019, 6:23 p.m.
Message ID <5292325009aa674d78d114d85bdbce94c3aec909.1551291557.git-series.mac@mcrowe.com>
Download mbox | patch
Permalink /patch/31627/
State New
Headers show

Comments

Mike Crowe - Feb. 27, 2019, 6:23 p.m.
As recommended by the comments in the implementations of
pthread_rwlock_timedrdlock and pthread_rwlock_timedwrlock, let's move the
timeout validity checks into the corresponding pthread_rwlock_rdlock_full
and pthread_rwlock_wrlock_full functions. Since these functions may be
called with abstime == NULL, an extra check for that is necessary too.
---
 nptl/pthread_rwlock_common.c      | 20 ++++++++++++++++++++
 nptl/pthread_rwlock_timedrdlock.c | 10 ----------
 nptl/pthread_rwlock_timedwrlock.c | 10 ----------
 3 files changed, 20 insertions(+), 20 deletions(-)
Adhemerval Zanella Netto - March 5, 2019, 4:48 p.m.
On 27/02/2019 15:23, Mike Crowe wrote:
> As recommended by the comments in the implementations of
> pthread_rwlock_timedrdlock and pthread_rwlock_timedwrlock, let's move the
> timeout validity checks into the corresponding pthread_rwlock_rdlock_full
> and pthread_rwlock_wrlock_full functions. Since these functions may be
> called with abstime == NULL, an extra check for that is necessary too.
> ---
>  nptl/pthread_rwlock_common.c      | 20 ++++++++++++++++++++
>  nptl/pthread_rwlock_timedrdlock.c | 10 ----------
>  nptl/pthread_rwlock_timedwrlock.c | 10 ----------
>  3 files changed, 20 insertions(+), 20 deletions(-)
> 
> diff --git a/nptl/pthread_rwlock_common.c b/nptl/pthread_rwlock_common.c
> index 89ba21a..120b880 100644
> --- a/nptl/pthread_rwlock_common.c
> +++ b/nptl/pthread_rwlock_common.c
> @@ -282,6 +282,16 @@ __pthread_rwlock_rdlock_full (pthread_rwlock_t *rwlock,
>  {
>    unsigned int r;
>  
> +  /* Make sure any passed in timeout value is valid.  Note that the previous
> +     implementation assumed that this check *must* not be performed if there
> +     would in fact be no blocking; however, POSIX only requires that "the
> +     validity of the abstime parameter need not be checked if the lock can be
> +     immediately acquired" (i.e., we need not but may check it).  */
> +  if (abstime
> +      && __glibc_unlikely (abstime->tv_nsec >= 1000000000
> +      || abstime->tv_nsec < 0))
> +    return EINVAL;
> +

Couldn't we create a consolidate implementation for this check instead of
duplicate it?

>    /* Make sure we are not holding the rwlock as a writer.  This is a deadlock
>       situation we recognize and report.  */
>    if (__glibc_unlikely (atomic_load_relaxed (&rwlock->__data.__cur_writer)
> @@ -576,6 +586,16 @@ static __always_inline int
>  __pthread_rwlock_wrlock_full (pthread_rwlock_t *rwlock,
>      const struct timespec *abstime)
>  {
> +  /* Make sure any passed in timeout value is valid.  Note that the previous
> +     implementation assumed that this check *must* not be performed if there
> +     would in fact be no blocking; however, POSIX only requires that "the
> +     validity of the abstime parameter need not be checked if the lock can be
> +     immediately acquired" (i.e., we need not but may check it).  */
> +  if (abstime
> +      && __glibc_unlikely (abstime->tv_nsec >= 1000000000
> +      || abstime->tv_nsec < 0))
> +    return EINVAL;
> +
>    /* Make sure we are not holding the rwlock as a writer.  This is a deadlock
>       situation we recognize and report.  */
>    if (__glibc_unlikely (atomic_load_relaxed (&rwlock->__data.__cur_writer)
> diff --git a/nptl/pthread_rwlock_timedrdlock.c b/nptl/pthread_rwlock_timedrdlock.c
> index aa00530..84c1983 100644
> --- a/nptl/pthread_rwlock_timedrdlock.c
> +++ b/nptl/pthread_rwlock_timedrdlock.c
> @@ -23,15 +23,5 @@ int
>  pthread_rwlock_timedrdlock (pthread_rwlock_t *rwlock,
>      const struct timespec *abstime)
>  {
> -  /* Make sure the passed in timeout value is valid.  Note that the previous
> -     implementation assumed that this check *must* not be performed if there
> -     would in fact be no blocking; however, POSIX only requires that "the
> -     validity of the abstime parameter need not be checked if the lock can be
> -     immediately acquired" (i.e., we need not but may check it).  */
> -  /* ??? Just move this to __pthread_rwlock_rdlock_full?  */
> -  if (__glibc_unlikely (abstime->tv_nsec >= 1000000000
> -      || abstime->tv_nsec < 0))
> -    return EINVAL;
> -
>    return __pthread_rwlock_rdlock_full (rwlock, abstime);
>  }
> diff --git a/nptl/pthread_rwlock_timedwrlock.c b/nptl/pthread_rwlock_timedwrlock.c
> index 3c92e44..f0b745d 100644
> --- a/nptl/pthread_rwlock_timedwrlock.c
> +++ b/nptl/pthread_rwlock_timedwrlock.c
> @@ -23,15 +23,5 @@ int
>  pthread_rwlock_timedwrlock (pthread_rwlock_t *rwlock,
>      const struct timespec *abstime)
>  {
> -  /* Make sure the passed in timeout value is valid.  Note that the previous
> -     implementation assumed that this check *must* not be performed if there
> -     would in fact be no blocking; however, POSIX only requires that "the
> -     validity of the abstime parameter need not be checked if the lock can be
> -     immediately acquired" (i.e., we need not but may check it).  */
> -  /* ??? Just move this to __pthread_rwlock_wrlock_full?  */
> -  if (__glibc_unlikely (abstime->tv_nsec >= 1000000000
> -      || abstime->tv_nsec < 0))
> -    return EINVAL;
> -
>    return __pthread_rwlock_wrlock_full (rwlock, abstime);
>  }
>

Patch

diff --git a/nptl/pthread_rwlock_common.c b/nptl/pthread_rwlock_common.c
index 89ba21a..120b880 100644
--- a/nptl/pthread_rwlock_common.c
+++ b/nptl/pthread_rwlock_common.c
@@ -282,6 +282,16 @@  __pthread_rwlock_rdlock_full (pthread_rwlock_t *rwlock,
 {
   unsigned int r;
 
+  /* Make sure any passed in timeout value is valid.  Note that the previous
+     implementation assumed that this check *must* not be performed if there
+     would in fact be no blocking; however, POSIX only requires that "the
+     validity of the abstime parameter need not be checked if the lock can be
+     immediately acquired" (i.e., we need not but may check it).  */
+  if (abstime
+      && __glibc_unlikely (abstime->tv_nsec >= 1000000000
+      || abstime->tv_nsec < 0))
+    return EINVAL;
+
   /* Make sure we are not holding the rwlock as a writer.  This is a deadlock
      situation we recognize and report.  */
   if (__glibc_unlikely (atomic_load_relaxed (&rwlock->__data.__cur_writer)
@@ -576,6 +586,16 @@  static __always_inline int
 __pthread_rwlock_wrlock_full (pthread_rwlock_t *rwlock,
     const struct timespec *abstime)
 {
+  /* Make sure any passed in timeout value is valid.  Note that the previous
+     implementation assumed that this check *must* not be performed if there
+     would in fact be no blocking; however, POSIX only requires that "the
+     validity of the abstime parameter need not be checked if the lock can be
+     immediately acquired" (i.e., we need not but may check it).  */
+  if (abstime
+      && __glibc_unlikely (abstime->tv_nsec >= 1000000000
+      || abstime->tv_nsec < 0))
+    return EINVAL;
+
   /* Make sure we are not holding the rwlock as a writer.  This is a deadlock
      situation we recognize and report.  */
   if (__glibc_unlikely (atomic_load_relaxed (&rwlock->__data.__cur_writer)
diff --git a/nptl/pthread_rwlock_timedrdlock.c b/nptl/pthread_rwlock_timedrdlock.c
index aa00530..84c1983 100644
--- a/nptl/pthread_rwlock_timedrdlock.c
+++ b/nptl/pthread_rwlock_timedrdlock.c
@@ -23,15 +23,5 @@  int
 pthread_rwlock_timedrdlock (pthread_rwlock_t *rwlock,
     const struct timespec *abstime)
 {
-  /* Make sure the passed in timeout value is valid.  Note that the previous
-     implementation assumed that this check *must* not be performed if there
-     would in fact be no blocking; however, POSIX only requires that "the
-     validity of the abstime parameter need not be checked if the lock can be
-     immediately acquired" (i.e., we need not but may check it).  */
-  /* ??? Just move this to __pthread_rwlock_rdlock_full?  */
-  if (__glibc_unlikely (abstime->tv_nsec >= 1000000000
-      || abstime->tv_nsec < 0))
-    return EINVAL;
-
   return __pthread_rwlock_rdlock_full (rwlock, abstime);
 }
diff --git a/nptl/pthread_rwlock_timedwrlock.c b/nptl/pthread_rwlock_timedwrlock.c
index 3c92e44..f0b745d 100644
--- a/nptl/pthread_rwlock_timedwrlock.c
+++ b/nptl/pthread_rwlock_timedwrlock.c
@@ -23,15 +23,5 @@  int
 pthread_rwlock_timedwrlock (pthread_rwlock_t *rwlock,
     const struct timespec *abstime)
 {
-  /* Make sure the passed in timeout value is valid.  Note that the previous
-     implementation assumed that this check *must* not be performed if there
-     would in fact be no blocking; however, POSIX only requires that "the
-     validity of the abstime parameter need not be checked if the lock can be
-     immediately acquired" (i.e., we need not but may check it).  */
-  /* ??? Just move this to __pthread_rwlock_wrlock_full?  */
-  if (__glibc_unlikely (abstime->tv_nsec >= 1000000000
-      || abstime->tv_nsec < 0))
-    return EINVAL;
-
   return __pthread_rwlock_wrlock_full (rwlock, abstime);
 }