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authorUlrich Drepper <drepper@redhat.com>1998-03-11 12:42:25 +0000
committerUlrich Drepper <drepper@redhat.com>1998-03-11 12:42:25 +0000
commit5afdca0087dad2994ad4fcdfe7f489f4dbcab7b3 (patch)
treec9c82db2ff92537b921361a02a284b0e18a594b8 /linuxthreads/rwlock.c
parent3d76e7784700c20fc222920b2a22baba006daa15 (diff)
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LinuxThreads library.
1998-03-11 00:42 Wolfram Gloger <wmglo@dent.med.uni-muenchen.de> * linuxthreads/manager.c: Enable resetting of the thread scheduling policy to SCHED_OTHER when the parent thread has a different one. 1998-02-01 13:51 Ulrich Drepper <drepper@cygnus.com> * sysdeps/unix/sysv/linux/bits/posix_opt.h: Define _POSIX_ASYNCHRONOUS_IO. * sysdeps/pthread/pthread.h: Define bits for Unix98 variants of mutexes. * mutex.c: Implement new mutex types. * internals.h: Include <signal.h>. * libpthread.map: Add __erno_location and __h_errno_location. * errno.c: Return pointer to variable actually in use. This might not be the one in the thread structure. * internals.h (struct _pthread_descr_struct): Add new fields p_errnop and p_h_errnop. * manager.c (__pthread_manager): Set p_errnop and p_h_errnop member of manager thread structure. (pthread_handle_create): Set p_errnop and p_h_errnop members for new thread. * pthread.c: Adapt initializer for thread structures. (__pthread_initial_thread): Set p_errnop and p_h_errnop member. (__pthread_reset_main_thread): Reset p_errnop and p_h_errnop of current thread to global variables. 1998-01-31 17:27 Ulrich Drepper <drepper@cygnus.com> * rwlock.c: New file. * Makefile (libpthread-routines): Add rwlock. * sysdeps/pthread/pthread.h: Define data structures and declare functions. * libpthread.map: Add new functions. 1997-12-18 13:50 Philip Blundell <pb@nexus.co.uk> * sysdeps/arm/pt-machine.h: New file; add ARM support. * sysdeps/arm/Implies: likewise. * README: Document it. 1997-12-13 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * signals.c: Remove unneeded initializer for sigwaited, saving a 1997-04-11 01:18 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * semaphore.c (sem_init): Set sem_spinlock only if available. 1997-12-04 01:48 Ulrich Drepper <drepper@cygnus.com> * mutex.c: Implement PTHREAD_MUTEX_CHECKERROR. * sysdeps/pthread/pthread.h: Define PTHREAD_MUTEX_CHECKERROR. * Makefile: Update from LinuxThreads 0.7. * internals.h. Likewise. * manager.c: Likewise. * mutex.c: Likewise. * pthread.c: Likewise. * signals.c: Likewise. * specific.c: Likewise. * Examples/ex3.c: Likewise. 1997-11-20 18:13 Ulrich Drepper <drepper@cygnus.com> * pthread.c (__pthread_reset_main_thread): Close pipe only if still open. 1997-10-29 05:38 Ulrich Drepper <drepper@cygnus.com> * wrapsyscall.c: Add socket functions which are also cancelation points. 1997-10-19 21:40 Wolfram Gloger <wg@wolfram.dent.med.uni-muenchen.de> * specific.c (__libc_internal_tsd_set, __libc_internal_tsd_get): New functions for fast thread specific data within libc. * internals.h: Add new array p_libc_specific to struct _pthread_descr_struct. * sysdeps/pthread/bits/libc-lock.h: Declare new functions. 1997-10-13 05:39 Ulrich Drepper <drepper@cygnus.com> * semaphore.h: Add __BEGIN_DECLS/__END_DECLS. Reported by Ralf Corsepius <corsepiu@faw.uni-ulm.de>. 1997-08-29 03:05 Ulrich Drepper <drepper@cygnus.com> * internals.h (struct _pthread_descr_struct): Add definitions for two-level specific key handling. * manager.c (pthread_handle_create): Initialize specific memory array. * specific.c: Implement two-level key handling. * weaks.c: Don't provide dummy key handling. * sysdeps/pthread/bits/libc-lock.h: Typedef __libc_lock_t (no #define). Add definition of __libc_key_t. * sysdeps/unix/sysv/linux/bits/local_lim.h: Define PTHREAD_KEYS_MAX as 1024. Add definition of _POSIX_THREAD_DESTRUCTOR_ITERATIONS and PTHREAD_DESTRUCTOR_ITERATIONS. * manager.c (pthread_handle_create): Compare mmap result with MAP_FAILED. * ptfork.c: Rename to __pthread_atfork and make old name a weak alias. * sysdeps/pthread/bits/pthread.h: Add prototype for __pthread_atfork. 1997-08-22 19:04 Richard Henderson <rth@cygnus.com> sysdeps/sparc -> sysdeps/sparc/sparc32 sysdeps/sparc64 -> sysdeps/sparc/sparc64 * internals.h: Change definition of THREAD_SELF to be an expression, not a statement that did a return. * sysdeps/alpha/pt-machine.h (THREAD_SELF): Update accordingly. * sysdeps/sparc/sparc32/pt-machine.h (THREAD_SELF, INIT_THREAD_SELF): Follow Solaris and use a "system reserved" register (%g6) to hold the thread descriptor. * sysdeps/sparc/sparc64/pt-machine.h: Likewise. 1997-08-03 00:09 Ulrich Drepper <drepper@cygnus.com> * mutex.c: Correct pthread_once. Patch by Xavier Leroy. * sysdeps/pthread/pthread.h: Add prototype for __pthread_once. * sysdeps/pthread/bits/pthread.h: Add macros for __libc_once. * semaphore.c: Include spinlock.h only when needed. * specific.c (__pthread_setsepcific, __pthread_getspecific): Reject keys for entries not in use. * weaks.c: Implement key handling functions for real. 1997-06-29 01:04 Richard Henderson <richard@gnu.ai.mit.edu> Initial sparc64-linux support: * linuxthreads/sysdeps/sparc64/Implies: New file. * linuxthreads/sysdeps/sparc64/pt-machine.h: Likewise. 1997-06-29 00:48 Ulrich Drepper <drepper@cygnus.com> * semaphore.c: Include spinlock.h at correct place. Patch by HJ Lu. 1997-06-13 10:06 Richard Henderson <rth@tamu.edu> The Great Bit File Move: * sysdeps/alpha/semaphorebits.h: -> .../bits/semaphore.h. * sysdeps/powerpc/semaphorebits.h: Likewise. * sysdeps/pthread/cmpxchg/semaphorebits.h: Likewise. * sysdeps/pthread/no-cmpxchg/semaphorebits.h: Likewise. * sysdeps/pthread/libc-lock.h: -> bits/ * sysdeps/pthread/stdio-lock.h: Likewise. * sysdeps/unix/sysv/linux/local_lim.h: Likewise. * sysdeps/unix/sysv/linux/posix_opt.h: Likewise. * semaphore.h: Likewise. * sysdeps/pthread/pthread.h: Likewise. * lockfile.c: <foo.h> -> <bits/foo.h>. * semaphore.h: Likewise. * Makefile: (headers): foo.h -> bits/foo.h. * sysdeps/pthread/Makefile: Likewise. 1997-04-11 01:18 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * semaphore.c (sem_init): Set sem_spinlock only if available. * sysdeps/m68k/pt-machine.h (testandset, __compare_and_swap): Fix asm constraints. 1997-04-09 03:00 Ulrich Drepper <drepper@cygnus.com> Update from LinuxThreads 0.6. * attr.c (pthread_attr_getdetachstate): Use __sched_get_priority_max and __sched_get_priority_min instead of names without `__'. * manager.c: Rewrite large parts to implement opaque pthread_t. * cancel.c: Adapt for opaque pthread_t type. * condvar.c: Likewise. * errno.c: Likewise. * join.c: Likewise. * mutex.c: Likewise. * pthread.c: Likewise. * signals.c: Likewise. * specific.c: Likewise. * restart.h: Likewise. * queue.h: Likewise. * Examples/ex3.c: Likewise. * Examples/ex4.c: Likewise. * sysdeps/pthread/pthread.h: Likewise. * pthread.c: Accumulate time for all threads in thread manager. * semaphore.c: Implement fallback implementation for architectures sometimes missing compare-exchange operations. * cancel.c (pthread_cancel): Validate handle argument. * join.c (pthread_join): Likewise. (pthread_detach): Likewise. * signals.c (pthread_kill): Likewise. * spinlock.h (acquire): Use __sched_yield not sched_yield. * queue.h (enqueue): Enqueue thread according to priority. * internals.c (struct pthread_start_args): New struct for passing args to cloning function. (struct _pthread): Rename to _pthread_descr_struct and adapt for opaque pthread_t. * Examples/Makefile (clean): Pass -f option to rm. * sysdeps/i386/pt-machine.h: Add check for compare-exchange instruction and define TEST_FOR_COMPARE_AND_SWAP. * sysdeps/i386/i486/pt-machine.h: Removed. * sysdeps/unix/sysv/linux/local_lim.h (PTHREAD_THREADS_MAX): Increase to 1024. 1997-04-04 16:38 Ulrich Drepper <drepper@cygnus.com> * restart.h (suspend): Clear p_signal before suspending. (suspend_with_cancellation): Likewise. Patch by Xavier Leroy <Xavier.Leroy@inria.fr>. * weaks.c: Make __pthread_key_create return 1. * sysdeps/pthread/libc-lock.h: Define __libc_key_create, __libc_getspecific, __libc_setspecific, and __libc_key_t. * sysdeps/pthread/stdio-lock.h: Don't care for implementation not using libio. 1997-03-19 15:13 Miguel de Icaza <miguel@nuclecu.unam.mx> * sysdeps/sparc/pt-machine (RELEASE): Fix. 1997-03-01 07:55 Geoff Keating <geoffk@ozemail.com.au> * sysdeps/powerpc/Implies: Added. * sysdeps/powerpc/pt-machine.h: Added. * sysdeps/powerpc/semaphorebits.h: Added. 1997-01-22 01:22 Ulrich Drepper <drepper@cygnus.com> * linuxtheads/pthread.c (__pthread_initial_thread): Correct initializer. (__pthread_manager_thread): Likewise. Reported by Andreas Jaeger. 1997-01-18 22:15 Richard Henderson <rth@tamu.edu> Since sigset_t no longer fits in a register, we can't pass in the thread's initial mask so easily. Take this opportunity to simplify the clone implementation by only accepting a single void* argument. * linuxthreads/manager.c (__pthread_manager): Put thread vitals in the thread struct instead of as arguments through clone. (pthread_start_thread): Look for them there. * linuxthreads/internals.h (struct _pthread): Add p_initial_fn, p_initial_fn_arg, p_initial_mask. Fix __pthread_manager proto. * linuxthreads/pthread.c (pthread_initialize_manager): Revise clone invocation.
Diffstat (limited to 'linuxthreads/rwlock.c')
-rw-r--r--linuxthreads/rwlock.c276
1 files changed, 276 insertions, 0 deletions
diff --git a/linuxthreads/rwlock.c b/linuxthreads/rwlock.c
new file mode 100644
index 0000000000..c6b281551a
--- /dev/null
+++ b/linuxthreads/rwlock.c
@@ -0,0 +1,276 @@
+/* Read-write lock implementation.
+ Copyright (C) 1998 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
+ 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.
+
+ 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,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <errno.h>
+#include <pthread.h>
+#include "internals.h"
+#include "queue.h"
+#include "restart.h"
+#include "spinlock.h"
+
+int
+pthread_rwlock_init (pthread_rwlock_t *rwlock,
+ const pthread_rwlockattr_t *attr)
+{
+ rwlock->rw_spinlock = 0;
+ rwlock->rw_readers = 0;
+ rwlock->rw_writer = NULL;
+
+ queue_init(&rwlock->rw_read_waiting);
+ queue_init(&rwlock->rw_write_waiting);
+
+ if (attr == NULL)
+ {
+ rwlock->rw_kind = PTHREAD_RWLOCK_DEFAULT_NP;
+ rwlock->rw_pshared = PTHREAD_PROCESS_PRIVATE;
+ }
+ else
+ {
+ rwlock->rw_kind = attr->lockkind;
+ rwlock->rw_pshared = attr->pshared;
+ }
+
+ return 0;
+}
+
+
+int
+pthread_rwlock_destroy (pthread_rwlock_t *rwlock)
+{
+ int readers;
+ _pthread_descr writer;
+
+ acquire (&rwlock->rw_spinlock);
+ readers = rwlock->rw_readers;
+ writer = rwlock->rw_writer;
+ release (&rwlock->rw_spinlock);
+
+ if (readers > 0 || writer != NULL)
+ return EBUSY;
+
+ return 0;
+}
+
+
+int
+pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
+{
+ pthread_descr self;
+
+ while (1)
+ {
+ acquire (&rwlock->rw_spinlock);
+ if (rwlock->rw_writer == NULL
+ || (rwlock->rw_kind == PTHREAD_RWLOCK_PREFER_READER_NP
+ && rwlock->rw_readers != 0))
+ /* We can add a reader lock. */
+ break;
+
+ /* Suspend ourselves, then try again */
+ self = thread_self ();
+ enqueue (&rwlock->rw_read_waiting, self);
+ release (&rwlock->rw_spinlock);
+ suspend (self); /* This is not a cancellation point */
+ }
+
+ ++rwlock->rw_readers;
+ release (&rwlock->rw_spinlock);
+
+ return 0;
+}
+
+
+int
+pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
+{
+ int result = EBUSY;
+
+ acquire (&rwlock->rw_spinlock);
+ if (rwlock->rw_writer == NULL
+ || (rwlock->rw_kind == PTHREAD_RWLOCK_PREFER_READER_NP
+ && rwlock->rw_readers != 0))
+ {
+ ++rwlock->rw_readers;
+ result = 0;
+ }
+ release (&rwlock->rw_spinlock);
+
+ return result;
+}
+
+
+int
+pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
+{
+ pthread_descr self = thread_self ();
+
+ while(1)
+ {
+ acquire (&rwlock->rw_spinlock);
+ if (rwlock->rw_readers == 0 && rwlock->rw_writer == NULL)
+ {
+ rwlock->rw_writer = self;
+ release (&rwlock->rw_spinlock);
+ return 0;
+ }
+
+ /* Suspend ourselves, then try again */
+ enqueue (&rwlock->rw_write_waiting, self);
+ release (&rwlock->rw_spinlock);
+ suspend (self); /* This is not a cancellation point */
+ }
+}
+
+
+int
+pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock)
+{
+ int result = EBUSY;
+
+ acquire (&rwlock->rw_spinlock);
+ if (rwlock->rw_readers == 0 && rwlock->rw_writer == NULL)
+ {
+ rwlock->rw_writer = thread_self ();
+ result = 0;
+ }
+ release (&rwlock->rw_spinlock);
+
+ return result;
+}
+
+
+int
+pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
+{
+ struct _pthread_queue torestart;
+ pthread_descr th;
+
+ acquire (&rwlock->rw_spinlock);
+ if (rwlock->rw_writer != NULL)
+ {
+ /* Unlocking a write lock. */
+ if (rwlock->rw_writer != thread_self ())
+ {
+ release (&rwlock->rw_spinlock);
+ return EPERM;
+ }
+ rwlock->rw_writer = NULL;
+
+ if (rwlock->rw_kind == PTHREAD_RWLOCK_PREFER_READER_NP
+ || (th = dequeue (&rwlock->rw_write_waiting)) == NULL)
+ {
+ /* Restart all waiting readers. */
+ torestart = rwlock->rw_read_waiting;
+ queue_init (&rwlock->rw_read_waiting);
+ release (&rwlock->rw_spinlock);
+ while ((th = dequeue (&torestart)) != NULL)
+ restart (th);
+ }
+ else
+ {
+ /* Restart one waiting writer. */
+ release (&rwlock->rw_spinlock);
+ restart (th);
+ }
+ }
+ else
+ {
+ /* Unlocking a read lock. */
+ if (rwlock->rw_readers == 0)
+ {
+ release (&rwlock->rw_spinlock);
+ return EPERM;
+ }
+
+ --rwlock->rw_readers;
+ if (rwlock->rw_readers == 0)
+ /* Restart one waiting writer, if any. */
+ th = dequeue (&rwlock->rw_write_waiting);
+ else
+ th = NULL;
+
+ release (&rwlock->rw_spinlock);
+ if (th != NULL)
+ restart (th);
+ }
+
+ return 0;
+}
+
+
+
+int
+pthread_rwlockattr_init (pthread_rwlockattr_t *attr)
+{
+ attr->lockkind = 0;
+ attr->pshared = 0;
+
+ return 0;
+}
+
+
+int
+pthread_rwlockattr_destroy (pthread_rwlockattr_t *attr)
+{
+ return 0;
+}
+
+
+int
+pthread_rwlockattr_getpshared (const pthread_rwlockattr_t *attr, int *pshared)
+{
+ *pshared = attr->pshared;
+ return 0;
+}
+
+
+int
+pthread_rwlockattr_setpshared (pthread_rwlockattr_t *attr, int pshared)
+{
+ if (pshared != PTHREAD_PROCESS_PRIVATE && pshared != PTHREAD_PROCESS_SHARED)
+ return EINVAL;
+
+ attr->pshared = pshared;
+
+ return 0;
+}
+
+
+int
+pthread_rwlockattr_getkind_np (const pthread_rwlockattr_t *attr, int *pref)
+{
+ *pref = attr->lockkind;
+ return 0;
+}
+
+
+int
+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_DEFAULT_NP)
+ return EINVAL;
+
+ attr->lockkind = pref;
+
+ return 0;
+}