diff options
author | Ulrich Drepper <drepper@redhat.com> | 2000-06-26 08:01:33 +0000 |
---|---|---|
committer | Ulrich Drepper <drepper@redhat.com> | 2000-06-26 08:01:33 +0000 |
commit | c49ebf7645b828a4a82b69791dc23e19b7264e21 (patch) | |
tree | 235fa4a4995064709979e7b7b4faec8568efd928 /linuxthreads/rwlock.c | |
parent | d82e4c7bb231c9e0f835bd46467563ac3b56cebe (diff) | |
download | glibc-c49ebf7645b828a4a82b69791dc23e19b7264e21.tar.gz glibc-c49ebf7645b828a4a82b69791dc23e19b7264e21.tar.xz glibc-c49ebf7645b828a4a82b69791dc23e19b7264e21.zip |
Update.
2000-06-26 Ulrich Drepper <drepper@redhat.com> * Makefile (tests): Add ex11. Add rules to build it. * Examples/ex11.c: New file. * rwlock.c: Fix complete braindamaged previous try to implement timedout functions. * spinlock.c: Pretty print.
Diffstat (limited to 'linuxthreads/rwlock.c')
-rw-r--r-- | linuxthreads/rwlock.c | 136 |
1 files changed, 108 insertions, 28 deletions
diff --git a/linuxthreads/rwlock.c b/linuxthreads/rwlock.c index 6ee5b62247..2bcdf97de0 100644 --- a/linuxthreads/rwlock.c +++ b/linuxthreads/rwlock.c @@ -27,6 +27,35 @@ #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) +{ + volatile pthread_descr self = thread_self(); + pthread_rwlock_t *rwlock = obj; + int did_remove = 0; + + __pthread_lock((struct _pthread_fastlock *) &rwlock->__rw_lock, self); + did_remove = remove_from_queue(&rwlock->__rw_read_waiting, th); + __pthread_unlock((struct _pthread_fastlock *) &rwlock->__rw_lock); + + return did_remove; +} + +static int rwlock_wr_extricate_func(void *obj, pthread_descr th) +{ + volatile pthread_descr self = thread_self(); + pthread_rwlock_t *rwlock = obj; + int did_remove = 0; + + __pthread_lock((struct _pthread_fastlock *) &rwlock->__rw_lock, self); + did_remove = remove_from_queue(&rwlock->__rw_write_waiting, th); + __pthread_unlock((struct _pthread_fastlock *) &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 @@ -214,10 +243,10 @@ __pthread_rwlock_destroy (pthread_rwlock_t *rwlock) int readers; _pthread_descr writer; - __pthread_alt_lock (&rwlock->__rw_lock, NULL); + __pthread_lock (&rwlock->__rw_lock, NULL); readers = rwlock->__rw_readers; writer = rwlock->__rw_writer; - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); if (readers > 0 || writer != NULL) return EBUSY; @@ -241,18 +270,18 @@ __pthread_rwlock_rdlock (pthread_rwlock_t *rwlock) for (;;) { - __pthread_alt_lock (&rwlock->__rw_lock, self); + __pthread_lock (&rwlock->__rw_lock, self); if (rwlock_can_rdlock(rwlock, have_lock_already)) break; enqueue (&rwlock->__rw_read_waiting, self); - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); suspend (self); /* This is not a cancellation point */ } ++rwlock->__rw_readers; - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); if (have_lock_already || out_of_mem) { @@ -273,6 +302,7 @@ __pthread_rwlock_timedrdlock (pthread_rwlock_t *rwlock, 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; @@ -283,21 +313,46 @@ __pthread_rwlock_timedrdlock (pthread_rwlock_t *rwlock, 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 (;;) { - if (__pthread_alt_timedlock (&rwlock->__rw_lock, self, abstime) == 0) - return ETIMEDOUT; + __pthread_lock (&rwlock->__rw_lock, self); if (rwlock_can_rdlock(rwlock, have_lock_already)) break; enqueue (&rwlock->__rw_read_waiting, self); - __pthread_alt_unlock (&rwlock->__rw_lock); - suspend (self); /* This is not a cancellation point */ + __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_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); if (have_lock_already || out_of_mem) { @@ -322,7 +377,7 @@ __pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock) have_lock_already = rwlock_have_already(&self, rwlock, &existing, &out_of_mem); - __pthread_alt_lock (&rwlock->__rw_lock, self); + __pthread_lock (&rwlock->__rw_lock, self); /* 0 is passed to here instead of have_lock_already. This is to meet Single Unix Spec requirements: @@ -336,7 +391,7 @@ __pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock) retval = 0; } - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); if (retval == 0) { @@ -361,17 +416,17 @@ __pthread_rwlock_wrlock (pthread_rwlock_t *rwlock) while(1) { - __pthread_alt_lock (&rwlock->__rw_lock, self); + __pthread_lock (&rwlock->__rw_lock, self); if (rwlock->__rw_readers == 0 && rwlock->__rw_writer == NULL) { rwlock->__rw_writer = self; - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); return 0; } /* Suspend ourselves, then try again */ enqueue (&rwlock->__rw_write_waiting, self); - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); suspend (self); /* This is not a cancellation point */ } } @@ -383,28 +438,53 @@ __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) { - if (__pthread_alt_timedlock (&rwlock->__rw_lock, self, abstime) == 0) - return ETIMEDOUT; + __pthread_lock (&rwlock->__rw_lock, self); if (rwlock->__rw_readers == 0 && rwlock->__rw_writer == NULL) { rwlock->__rw_writer = self; - __pthread_alt_unlock (&rwlock->__rw_lock); + __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_alt_unlock (&rwlock->__rw_lock); - suspend (self); /* This is not a cancellation point */ + __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) @@ -415,13 +495,13 @@ __pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock) { int result = EBUSY; - __pthread_alt_lock (&rwlock->__rw_lock, NULL); + __pthread_lock (&rwlock->__rw_lock, NULL); if (rwlock->__rw_readers == 0 && rwlock->__rw_writer == NULL) { rwlock->__rw_writer = thread_self (); result = 0; } - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); return result; } @@ -434,13 +514,13 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock) pthread_descr torestart; pthread_descr th; - __pthread_alt_lock (&rwlock->__rw_lock, NULL); + __pthread_lock (&rwlock->__rw_lock, NULL); if (rwlock->__rw_writer != NULL) { /* Unlocking a write lock. */ if (rwlock->__rw_writer != thread_self ()) { - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); return EPERM; } rwlock->__rw_writer = NULL; @@ -452,14 +532,14 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock) /* Restart all waiting readers. */ torestart = rwlock->__rw_read_waiting; rwlock->__rw_read_waiting = NULL; - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); while ((th = dequeue (&torestart)) != NULL) restart (th); } else { /* Restart one waiting writer. */ - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); restart (th); } } @@ -468,7 +548,7 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock) /* Unlocking a read lock. */ if (rwlock->__rw_readers == 0) { - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); return EPERM; } @@ -479,7 +559,7 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock) else th = NULL; - __pthread_alt_unlock (&rwlock->__rw_lock); + __pthread_unlock (&rwlock->__rw_lock); if (th != NULL) restart (th); |