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author | Ulrich Drepper <drepper@redhat.com> | 1998-03-11 12:42:25 +0000 |
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committer | Ulrich Drepper <drepper@redhat.com> | 1998-03-11 12:42:25 +0000 |
commit | 5afdca0087dad2994ad4fcdfe7f489f4dbcab7b3 (patch) | |
tree | c9c82db2ff92537b921361a02a284b0e18a594b8 /linuxthreads/rwlock.c | |
parent | 3d76e7784700c20fc222920b2a22baba006daa15 (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.c | 276 |
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; +} |