diff --git a/include/sys/condvar.h b/include/sys/condvar.h index 6a2060fd2..3318ec595 100644 --- a/include/sys/condvar.h +++ b/include/sys/condvar.h @@ -20,6 +20,7 @@ typedef struct { wait_queue_head_t cv_event; atomic_t cv_waiters; kmutex_t *cv_mutex; /* only for verification purposes */ + spinlock_t cv_lock; } kcondvar_t; typedef enum { CV_DEFAULT=0, CV_DRIVER } kcv_type_t; @@ -33,13 +34,14 @@ cv_init(kcondvar_t *cvp, char *name, kcv_type_t type, void *arg) cvp->cv_magic = CV_MAGIC; init_waitqueue_head(&cvp->cv_event); + spin_lock_init(&cvp->cv_lock); atomic_set(&cvp->cv_waiters, 0); cvp->cv_mutex = NULL; cvp->cv_name = NULL; if (name) { - cvp->cv_name = kmalloc(strlen(name) + 1, GFP_KERNEL); - if (cvp->cv_name) + cvp->cv_name = kmalloc(strlen(name) + 1, GFP_KERNEL); + if (cvp->cv_name) strcpy(cvp->cv_name, name); } } @@ -48,6 +50,7 @@ static __inline__ void cv_destroy(kcondvar_t *cvp) { BUG_ON(cvp == NULL); + spin_lock(&cvp->cv_lock); BUG_ON(cvp->cv_magic != CV_MAGIC); BUG_ON(atomic_read(&cvp->cv_waiters) != 0); BUG_ON(waitqueue_active(&cvp->cv_event)); @@ -56,15 +59,16 @@ cv_destroy(kcondvar_t *cvp) kfree(cvp->cv_name); memset(cvp, CV_POISON, sizeof(*cvp)); + spin_unlock(&cvp->cv_lock); } static __inline__ void cv_wait(kcondvar_t *cvp, kmutex_t *mtx) { DEFINE_WAIT(wait); - int flag = 1; BUG_ON(cvp == NULL || mtx == NULL); + spin_lock(&cvp->cv_lock); BUG_ON(cvp->cv_magic != CV_MAGIC); BUG_ON(!mutex_owned(mtx)); @@ -73,37 +77,18 @@ cv_wait(kcondvar_t *cvp, kmutex_t *mtx) /* Ensure the same mutex is used by all callers */ BUG_ON(cvp->cv_mutex != mtx); + spin_unlock(&cvp->cv_lock); - for (;;) { - prepare_to_wait_exclusive(&cvp->cv_event, &wait, - TASK_INTERRUPTIBLE); - /* Must occur after we are added to the list but only once */ - if (flag) { - atomic_inc(&cvp->cv_waiters); - flag = 0; - } + prepare_to_wait_exclusive(&cvp->cv_event, &wait, + TASK_UNINTERRUPTIBLE); + atomic_inc(&cvp->cv_waiters); - /* XXX - The correct thing to do here may be to wake up and - * force the caller to handle the signal. Spurious wakeups - * should already be safely handled by the caller. */ - if (signal_pending(current)) - flush_signals(current); - - /* Mutex should be dropped after prepare_to_wait() this - * ensures we're linked in to the waiters list and avoids the - * race where 'cvp->cv_waiters > 0' but the list is empty. */ - mutex_exit(mtx); - schedule(); - mutex_enter(mtx); - - /* XXX - The correct thing to do here may be to wake up and - * force the caller to handle the signal. Spurious wakeups - * should already be safely handled by the caller. */ - if (signal_pending(current)) - continue; - - break; - } + /* Mutex should be dropped after prepare_to_wait() this + * ensures we're linked in to the waiters list and avoids the + * race where 'cvp->cv_waiters > 0' but the list is empty. */ + mutex_exit(mtx); + schedule(); + mutex_enter(mtx); atomic_dec(&cvp->cv_waiters); finish_wait(&cvp->cv_event, &wait); @@ -117,56 +102,34 @@ cv_timedwait(kcondvar_t *cvp, kmutex_t *mtx, clock_t expire_time) { DEFINE_WAIT(wait); clock_t time_left; - int flag = 1; BUG_ON(cvp == NULL || mtx == NULL); + spin_lock(&cvp->cv_lock); BUG_ON(cvp->cv_magic != CV_MAGIC); BUG_ON(!mutex_owned(mtx)); if (cvp->cv_mutex == NULL) cvp->cv_mutex = mtx; + /* Ensure the same mutex is used by all callers */ + BUG_ON(cvp->cv_mutex != mtx); + spin_unlock(&cvp->cv_lock); + /* XXX - Does not handle jiffie wrap properly */ time_left = expire_time - jiffies; if (time_left <= 0) return -1; - /* Ensure the same mutex is used by all callers */ - BUG_ON(cvp->cv_mutex != mtx); + prepare_to_wait_exclusive(&cvp->cv_event, &wait, + TASK_UNINTERRUPTIBLE); + atomic_inc(&cvp->cv_waiters); - for (;;) { - prepare_to_wait_exclusive(&cvp->cv_event, &wait, - TASK_INTERRUPTIBLE); - if (flag) { - atomic_inc(&cvp->cv_waiters); - flag = 0; - } - - /* XXX - The correct thing to do here may be to wake up and - * force the caller to handle the signal. Spurious wakeups - * should already be safely handled by the caller. */ - if (signal_pending(current)) - flush_signals(current); - - /* Mutex should be dropped after prepare_to_wait() this - * ensures we're linked in to the waiters list and avoids the - * race where 'cvp->cv_waiters > 0' but the list is empty. */ - mutex_exit(mtx); - time_left = schedule_timeout(time_left); - mutex_enter(mtx); - - /* XXX - The correct thing to do here may be to wake up and - * force the caller to handle the signal. Spurious wakeups - * should already be safely handled by the caller. */ - if (signal_pending(current)) { - if (time_left > 0) - continue; - - flush_signals(current); - } - - break; - } + /* Mutex should be dropped after prepare_to_wait() this + * ensures we're linked in to the waiters list and avoids the + * race where 'cvp->cv_waiters > 0' but the list is empty. */ + mutex_exit(mtx); + time_left = schedule_timeout(time_left); + mutex_enter(mtx); atomic_dec(&cvp->cv_waiters); finish_wait(&cvp->cv_event, &wait);