#include <linux/init.h>
#include <linux/module.h>
-/*
- * Initialize an rwsem:
- */
-void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key)
-{
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
- * Make sure we are not reinitializing a held semaphore:
- */
- debug_check_no_locks_freed((void *)sem, sizeof(*sem));
- lockdep_init_map(&sem->dep_map, name, key, 0);
-#endif
- sem->count = RWSEM_UNLOCKED_VALUE;
- spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
-
-EXPORT_SYMBOL(__init_rwsem);
-
struct rwsem_waiter {
struct list_head list;
struct task_struct *task;
#define RWSEM_WAITING_FOR_WRITE 0x00000002
};
+#if RWSEM_DEBUG
+#undef rwsemtrace
+void rwsemtrace(struct rw_semaphore *sem, const char *str)
+{
+ printk("sem=%p\n", sem);
+ printk("(sem)=%08lx\n", sem->count);
+ if (sem->debug)
+ printk("[%d] %s({%08lx})\n", current->pid, str, sem->count);
+}
+#endif
+
/*
* handle the lock release when processes blocked on it that can now run
* - if we come here from up_xxxx(), then:
struct list_head *next;
signed long oldcount, woken, loop;
+ rwsemtrace(sem, "Entering __rwsem_do_wake");
+
if (downgrading)
goto dont_wake_writers;
next->prev = &sem->wait_list;
out:
+ rwsemtrace(sem, "Leaving __rwsem_do_wake");
return sem;
/* undo the change to count, but check for a transition 1->0 */
{
struct rwsem_waiter waiter;
+ rwsemtrace(sem, "Entering rwsem_down_read_failed");
+
waiter.flags = RWSEM_WAITING_FOR_READ;
rwsem_down_failed_common(sem, &waiter,
RWSEM_WAITING_BIAS - RWSEM_ACTIVE_BIAS);
+
+ rwsemtrace(sem, "Leaving rwsem_down_read_failed");
return sem;
}
{
struct rwsem_waiter waiter;
+ rwsemtrace(sem, "Entering rwsem_down_write_failed");
+
waiter.flags = RWSEM_WAITING_FOR_WRITE;
rwsem_down_failed_common(sem, &waiter, -RWSEM_ACTIVE_BIAS);
+ rwsemtrace(sem, "Leaving rwsem_down_write_failed");
return sem;
}
{
unsigned long flags;
+ rwsemtrace(sem, "Entering rwsem_wake");
+
spin_lock_irqsave(&sem->wait_lock, flags);
/* do nothing if list empty */
spin_unlock_irqrestore(&sem->wait_lock, flags);
+ rwsemtrace(sem, "Leaving rwsem_wake");
+
return sem;
}
{
unsigned long flags;
+ rwsemtrace(sem, "Entering rwsem_downgrade_wake");
+
spin_lock_irqsave(&sem->wait_lock, flags);
/* do nothing if list empty */
spin_unlock_irqrestore(&sem->wait_lock, flags);
+ rwsemtrace(sem, "Leaving rwsem_downgrade_wake");
return sem;
}
EXPORT_SYMBOL(rwsem_down_write_failed);
EXPORT_SYMBOL(rwsem_wake);
EXPORT_SYMBOL(rwsem_downgrade_wake);
+#if RWSEM_DEBUG
+EXPORT_SYMBOL(rwsemtrace);
+#endif