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pthread_rwlock_timedrdlock() and pthread_rwlock_timedwrlock(): 

After exiting the try-again loop, make one more test of the lock
conditions, in case it was released while a signal handler kept the
thread busy past the alarm expiration.
This commit is contained in:
nathanw 2005-01-09 01:57:38 +00:00
parent 6a562a3a84
commit efffd0e96a
1 changed files with 12 additions and 4 deletions
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16
lib/libpthread/pthread_rwlock.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: pthread_rwlock.c,v 1.10 2005/01/09 01:47:20 nathanw Exp $ */
/* $NetBSD: pthread_rwlock.c,v 1.11 2005/01/09 01:57:38 nathanw Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
@ -37,7 +37,7 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: pthread_rwlock.c,v 1.10 2005/01/09 01:47:20 nathanw Exp $");
__RCSID("$NetBSD: pthread_rwlock.c,v 1.11 2005/01/09 01:57:38 nathanw Exp $");
#include <errno.h>
@ -296,8 +296,14 @@ pthread_rwlock_timedrdlock(pthread_rwlock_t *rwlock,
pthread_spinlock(self, &rwlock->ptr_interlock);
}
if (retval == 0)
/* One last chance to get the lock, in case it was released between
the alarm firing and when this thread got rescheduled, or in case
a signal handler kept it busy */
if ((rwlock->ptr_writer == NULL) &&
(PTQ_EMPTY(&rwlock->ptr_wblocked))) {
rwlock->ptr_nreaders++;
retval = 0;
}
pthread_spinunlock(self, &rwlock->ptr_interlock);
return retval;
@ -359,8 +365,10 @@ pthread_rwlock_timedwrlock(pthread_rwlock_t *rwlock,
pthread_spinlock(self, &rwlock->ptr_interlock);
}
if (retval == 0)
if ((rwlock->ptr_nreaders == 0) && (rwlock->ptr_writer == NULL)) {
rwlock->ptr_writer = self;
retval = 0;
}
pthread_spinunlock(self, &rwlock->ptr_interlock);
return retval;