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authorWaldemar Brodkorb <wbx@openadk.org>2015-02-14 23:04:02 -0600
committerWaldemar Brodkorb <wbx@openadk.org>2015-02-14 23:04:02 -0600
commite1e46622ac0fce73d802fa4a8a2e83cc25cd9e7a (patch)
tree2c8d14e4dcc733f4227f0984ed05da5826b13acd /libpthread/linuxthreads/rwlock.c
parent6b6ede3d15f04fe825cfa9f697507457e3640344 (diff)
Revert "resolve merge"
This reverts commit 6b6ede3d15f04fe825cfa9f697507457e3640344.
Diffstat (limited to 'libpthread/linuxthreads/rwlock.c')
-rw-r--r--libpthread/linuxthreads/rwlock.c250
1 files changed, 211 insertions, 39 deletions
diff --git a/libpthread/linuxthreads/rwlock.c b/libpthread/linuxthreads/rwlock.c
index 3ab940261..af72876f5 100644
--- a/libpthread/linuxthreads/rwlock.c
+++ b/libpthread/linuxthreads/rwlock.c
@@ -1,23 +1,24 @@
/* Read-write lock implementation.
- Copyright (C) 1998 Free Software Foundation, Inc.
+ Copyright (C) 1998, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Xavier Leroy <Xavier.Leroy@inria.fr>
and Ulrich Drepper <drepper@cygnus.com>, 1998.
The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Library General Public License as
- published by the Free Software Foundation; either version 2 of the
+ 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
- Library General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU Library General Public
- License along with the GNU C Library; see the file COPYING.LIB. If not,
- see <http://www.gnu.org/licenses/>. */
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If
+ not, see <http://www.gnu.org/licenses/>. */
+#include <bits/libc-lock.h>
#include <errno.h>
#include <pthread.h>
#include <stdlib.h>
@@ -26,6 +27,33 @@
#include "spinlock.h"
#include "restart.h"
+/* Function called by pthread_cancel to remove the thread from
+ waiting inside pthread_rwlock_timedrdlock or pthread_rwlock_timedwrlock. */
+
+static int rwlock_rd_extricate_func(void *obj, pthread_descr th)
+{
+ pthread_rwlock_t *rwlock = obj;
+ int did_remove = 0;
+
+ __pthread_lock(&rwlock->__rw_lock, NULL);
+ did_remove = remove_from_queue(&rwlock->__rw_read_waiting, th);
+ __pthread_unlock(&rwlock->__rw_lock);
+
+ return did_remove;
+}
+
+static int rwlock_wr_extricate_func(void *obj, pthread_descr th)
+{
+ pthread_rwlock_t *rwlock = obj;
+ int did_remove = 0;
+
+ __pthread_lock(&rwlock->__rw_lock, NULL);
+ did_remove = remove_from_queue(&rwlock->__rw_write_waiting, th);
+ __pthread_unlock(&rwlock->__rw_lock);
+
+ return did_remove;
+}
+
/*
* Check whether the calling thread already owns one or more read locks on the
* specified lock. If so, return a pointer to the read lock info structure
@@ -37,7 +65,8 @@ rwlock_is_in_list(pthread_descr self, pthread_rwlock_t *rwlock)
{
pthread_readlock_info *info;
- for (info = self->p_readlock_list; info != NULL; info = info->pr_next)
+ for (info = THREAD_GETMEM (self, p_readlock_list); info != NULL;
+ info = info->pr_next)
{
if (info->pr_lock == rwlock)
return info;
@@ -57,10 +86,10 @@ rwlock_is_in_list(pthread_descr self, pthread_rwlock_t *rwlock)
static pthread_readlock_info *
rwlock_add_to_list(pthread_descr self, pthread_rwlock_t *rwlock)
{
- pthread_readlock_info *info = self->p_readlock_free;
+ pthread_readlock_info *info = THREAD_GETMEM (self, p_readlock_free);
if (info != NULL)
- self->p_readlock_free = info->pr_next;
+ THREAD_SETMEM (self, p_readlock_free, info->pr_next);
else
info = malloc(sizeof *info);
@@ -69,8 +98,8 @@ rwlock_add_to_list(pthread_descr self, pthread_rwlock_t *rwlock)
info->pr_lock_count = 1;
info->pr_lock = rwlock;
- info->pr_next = self->p_readlock_list;
- self->p_readlock_list = info;
+ info->pr_next = THREAD_GETMEM (self, p_readlock_list);
+ THREAD_SETMEM (self, p_readlock_list, info);
return info;
}
@@ -160,11 +189,12 @@ rwlock_have_already(pthread_descr *pself, pthread_rwlock_t *rwlock,
if (rwlock->__rw_kind == PTHREAD_RWLOCK_PREFER_WRITER_NP)
{
if (!self)
- self = thread_self();
+ *pself = self = thread_self();
existing = rwlock_is_in_list(self, rwlock);
- if (existing != NULL || self->p_untracked_readlock_count > 0)
+ if (existing != NULL
+ || THREAD_GETMEM (self, p_untracked_readlock_count) > 0)
have_lock_already = 1;
else
{
@@ -176,14 +206,13 @@ rwlock_have_already(pthread_descr *pself, pthread_rwlock_t *rwlock,
*pout_of_mem = out_of_mem;
*pexisting = existing;
- *pself = self;
return have_lock_already;
}
int
-pthread_rwlock_init (pthread_rwlock_t *rwlock,
- const pthread_rwlockattr_t *attr)
+__pthread_rwlock_init (pthread_rwlock_t *rwlock,
+ const pthread_rwlockattr_t *attr)
{
__pthread_init_lock(&rwlock->__rw_lock);
rwlock->__rw_readers = 0;
@@ -204,10 +233,11 @@ pthread_rwlock_init (pthread_rwlock_t *rwlock,
return 0;
}
+strong_alias (__pthread_rwlock_init, pthread_rwlock_init)
int
-pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
+__pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
{
int readers;
_pthread_descr writer;
@@ -222,22 +252,23 @@ pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
return 0;
}
+strong_alias (__pthread_rwlock_destroy, pthread_rwlock_destroy)
int
-pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
+__pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
{
pthread_descr self = NULL;
pthread_readlock_info *existing;
int out_of_mem, have_lock_already;
have_lock_already = rwlock_have_already(&self, rwlock,
- &existing, &out_of_mem);
+ &existing, &out_of_mem);
+
+ if (self == NULL)
+ self = thread_self ();
for (;;)
{
- if (self == NULL)
- self = thread_self ();
-
__pthread_lock (&rwlock->__rw_lock, self);
if (rwlock_can_rdlock(rwlock, have_lock_already))
@@ -254,16 +285,88 @@ pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
if (have_lock_already || out_of_mem)
{
if (existing != NULL)
- existing->pr_lock_count++;
+ ++existing->pr_lock_count;
+ else
+ ++self->p_untracked_readlock_count;
+ }
+
+ return 0;
+}
+strong_alias (__pthread_rwlock_rdlock, pthread_rwlock_rdlock)
+
+int
+__pthread_rwlock_timedrdlock (pthread_rwlock_t *rwlock,
+ const struct timespec *abstime)
+{
+ pthread_descr self = NULL;
+ pthread_readlock_info *existing;
+ int out_of_mem, have_lock_already;
+ pthread_extricate_if extr;
+
+ if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
+ return EINVAL;
+
+ have_lock_already = rwlock_have_already(&self, rwlock,
+ &existing, &out_of_mem);
+
+ if (self == NULL)
+ self = thread_self ();
+
+ /* Set up extrication interface */
+ extr.pu_object = rwlock;
+ extr.pu_extricate_func = rwlock_rd_extricate_func;
+
+ /* Register extrication interface */
+ __pthread_set_own_extricate_if (self, &extr);
+
+ for (;;)
+ {
+ __pthread_lock (&rwlock->__rw_lock, self);
+
+ if (rwlock_can_rdlock(rwlock, have_lock_already))
+ break;
+
+ enqueue (&rwlock->__rw_read_waiting, self);
+ __pthread_unlock (&rwlock->__rw_lock);
+ /* This is not a cancellation point */
+ if (timedsuspend (self, abstime) == 0)
+ {
+ int was_on_queue;
+
+ __pthread_lock (&rwlock->__rw_lock, self);
+ was_on_queue = remove_from_queue (&rwlock->__rw_read_waiting, self);
+ __pthread_unlock (&rwlock->__rw_lock);
+
+ if (was_on_queue)
+ {
+ __pthread_set_own_extricate_if (self, 0);
+ return ETIMEDOUT;
+ }
+
+ /* Eat the outstanding restart() from the signaller */
+ suspend (self);
+ }
+ }
+
+ __pthread_set_own_extricate_if (self, 0);
+
+ ++rwlock->__rw_readers;
+ __pthread_unlock (&rwlock->__rw_lock);
+
+ if (have_lock_already || out_of_mem)
+ {
+ if (existing != NULL)
+ ++existing->pr_lock_count;
else
- self->p_untracked_readlock_count++;
+ ++self->p_untracked_readlock_count;
}
return 0;
}
+strong_alias (__pthread_rwlock_timedrdlock, pthread_rwlock_timedrdlock)
int
-pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
+__pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
{
pthread_descr self = thread_self();
pthread_readlock_info *existing;
@@ -294,18 +397,19 @@ pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
if (have_lock_already || out_of_mem)
{
if (existing != NULL)
- existing->pr_lock_count++;
+ ++existing->pr_lock_count;
else
- self->p_untracked_readlock_count++;
+ ++self->p_untracked_readlock_count;
}
}
return retval;
}
+strong_alias (__pthread_rwlock_tryrdlock, pthread_rwlock_tryrdlock)
int
-pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
+__pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
{
pthread_descr self = thread_self ();
@@ -325,10 +429,68 @@ pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
suspend (self); /* This is not a cancellation point */
}
}
+strong_alias (__pthread_rwlock_wrlock, pthread_rwlock_wrlock)
int
-pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
+__pthread_rwlock_timedwrlock (pthread_rwlock_t *rwlock,
+ const struct timespec *abstime)
+{
+ pthread_descr self;
+ pthread_extricate_if extr;
+
+ if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
+ return EINVAL;
+
+ self = thread_self ();
+
+ /* Set up extrication interface */
+ extr.pu_object = rwlock;
+ extr.pu_extricate_func = rwlock_wr_extricate_func;
+
+ /* Register extrication interface */
+ __pthread_set_own_extricate_if (self, &extr);
+
+ while(1)
+ {
+ __pthread_lock (&rwlock->__rw_lock, self);
+
+ if (rwlock->__rw_readers == 0 && rwlock->__rw_writer == NULL)
+ {
+ rwlock->__rw_writer = self;
+ __pthread_set_own_extricate_if (self, 0);
+ __pthread_unlock (&rwlock->__rw_lock);
+ return 0;
+ }
+
+ /* Suspend ourselves, then try again */
+ enqueue (&rwlock->__rw_write_waiting, self);
+ __pthread_unlock (&rwlock->__rw_lock);
+ /* This is not a cancellation point */
+ if (timedsuspend (self, abstime) == 0)
+ {
+ int was_on_queue;
+
+ __pthread_lock (&rwlock->__rw_lock, self);
+ was_on_queue = remove_from_queue (&rwlock->__rw_write_waiting, self);
+ __pthread_unlock (&rwlock->__rw_lock);
+
+ if (was_on_queue)
+ {
+ __pthread_set_own_extricate_if (self, 0);
+ return ETIMEDOUT;
+ }
+
+ /* Eat the outstanding restart() from the signaller */
+ suspend (self);
+ }
+ }
+}
+strong_alias (__pthread_rwlock_timedwrlock, pthread_rwlock_timedwrlock)
+
+
+int
+__pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
{
int result = EBUSY;
@@ -342,10 +504,11 @@ pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
return result;
}
+strong_alias (__pthread_rwlock_trywrlock, pthread_rwlock_trywrlock)
int
-pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
+__pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
{
pthread_descr torestart;
pthread_descr th;
@@ -361,8 +524,9 @@ pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
}
rwlock->__rw_writer = NULL;
- if (rwlock->__rw_kind == PTHREAD_RWLOCK_PREFER_READER_NP
- || (th = dequeue (&rwlock->__rw_write_waiting)) == NULL)
+ if ((rwlock->__rw_kind == PTHREAD_RWLOCK_PREFER_READER_NP
+ && !queue_is_empty(&rwlock->__rw_read_waiting))
+ || (th = dequeue(&rwlock->__rw_write_waiting)) == NULL)
{
/* Restart all waiting readers. */
torestart = rwlock->__rw_read_waiting;
@@ -409,20 +573,22 @@ pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
{
if (victim->pr_lock_count == 0)
{
- victim->pr_next = self->p_readlock_free;
- self->p_readlock_free = victim;
+ victim->pr_next = THREAD_GETMEM (self, p_readlock_free);
+ THREAD_SETMEM (self, p_readlock_free, victim);
}
}
else
{
- if (self->p_untracked_readlock_count > 0)
- self->p_untracked_readlock_count--;
+ int val = THREAD_GETMEM (self, p_untracked_readlock_count);
+ if (val > 0)
+ THREAD_SETMEM (self, p_untracked_readlock_count, val - 1);
}
}
}
return 0;
}
+strong_alias (__pthread_rwlock_unlock, pthread_rwlock_unlock)
@@ -430,17 +596,18 @@ int
pthread_rwlockattr_init (pthread_rwlockattr_t *attr)
{
attr->__lockkind = 0;
- attr->__pshared = 0;
+ attr->__pshared = PTHREAD_PROCESS_PRIVATE;
return 0;
}
int
-pthread_rwlockattr_destroy (pthread_rwlockattr_t *attr attribute_unused)
+__pthread_rwlockattr_destroy (pthread_rwlockattr_t *attr)
{
return 0;
}
+strong_alias (__pthread_rwlockattr_destroy, pthread_rwlockattr_destroy)
int
@@ -457,6 +624,10 @@ pthread_rwlockattr_setpshared (pthread_rwlockattr_t *attr, int pshared)
if (pshared != PTHREAD_PROCESS_PRIVATE && pshared != PTHREAD_PROCESS_SHARED)
return EINVAL;
+ /* For now it is not possible to shared a conditional variable. */
+ if (pshared != PTHREAD_PROCESS_PRIVATE)
+ return ENOSYS;
+
attr->__pshared = pshared;
return 0;
@@ -476,6 +647,7 @@ pthread_rwlockattr_setkind_np (pthread_rwlockattr_t *attr, int pref)
{
if (pref != PTHREAD_RWLOCK_PREFER_READER_NP
&& pref != PTHREAD_RWLOCK_PREFER_WRITER_NP
+ && pref != PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP
&& pref != PTHREAD_RWLOCK_DEFAULT_NP)
return EINVAL;