1 files changed, 0 insertions, 257 deletions
diff --git a/lib/rwsem.c b/lib/rwsem.c
deleted file mode 100644
index 3e3365e5665..00000000000
--- a/lib/rwsem.c
+++ /dev/null
@@ -1,257 +0,0 @@
-/* rwsem.c: R/W semaphores: contention handling functions
- *
- * Written by David Howells (dhowells@redhat.com).
- * Derived from arch/i386/kernel/semaphore.c
- */
-#include <linux/rwsem.h>
-#include <linux/sched.h>
-#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;
-	unsigned int flags;
-#define RWSEM_WAITING_FOR_READ	0x00000001
-#define RWSEM_WAITING_FOR_WRITE	0x00000002
-};
-
-/*
- * handle the lock release when processes blocked on it that can now run
- * - if we come here from up_xxxx(), then:
- *   - the 'active part' of count (&0x0000ffff) reached 0 (but may have changed)
- *   - the 'waiting part' of count (&0xffff0000) is -ve (and will still be so)
- *   - there must be someone on the queue
- * - the spinlock must be held by the caller
- * - woken process blocks are discarded from the list after having task zeroed
- * - writers are only woken if downgrading is false
- */
-static inline struct rw_semaphore *
-__rwsem_do_wake(struct rw_semaphore *sem, int downgrading)
-{
-	struct rwsem_waiter *waiter;
-	struct task_struct *tsk;
-	struct list_head *next;
-	signed long oldcount, woken, loop;
-
-	if (downgrading)
-		goto dont_wake_writers;
-
-	/* if we came through an up_xxxx() call, we only only wake someone up
-	 * if we can transition the active part of the count from 0 -> 1
-	 */
- try_again:
-	oldcount = rwsem_atomic_update(RWSEM_ACTIVE_BIAS, sem)
-						- RWSEM_ACTIVE_BIAS;
-	if (oldcount & RWSEM_ACTIVE_MASK)
-		goto undo;
-
-	waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
-
-	/* try to grant a single write lock if there's a writer at the front
-	 * of the queue - note we leave the 'active part' of the count
-	 * incremented by 1 and the waiting part incremented by 0x00010000
-	 */
-	if (!(waiter->flags & RWSEM_WAITING_FOR_WRITE))
-		goto readers_only;
-
-	/* We must be careful not to touch 'waiter' after we set ->task = NULL.
-	 * It is an allocated on the waiter's stack and may become invalid at
-	 * any time after that point (due to a wakeup from another source).
-	 */
-	list_del(&waiter->list);
-	tsk = waiter->task;
-	smp_mb();
-	waiter->task = NULL;
-	wake_up_process(tsk);
-	put_task_struct(tsk);
-	goto out;
-
-	/* don't want to wake any writers */
- dont_wake_writers:
-	waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
-	if (waiter->flags & RWSEM_WAITING_FOR_WRITE)
-		goto out;
-
-	/* grant an infinite number of read locks to the readers at the front
-	 * of the queue
-	 * - note we increment the 'active part' of the count by the number of
-	 *   readers before waking any processes up
-	 */
- readers_only:
-	woken = 0;
-	do {
-		woken++;
-
-		if (waiter->list.next == &sem->wait_list)
-			break;
-
-		waiter = list_entry(waiter->list.next,
-					struct rwsem_waiter, list);
-
-	} while (waiter->flags & RWSEM_WAITING_FOR_READ);
-
-	loop = woken;
-	woken *= RWSEM_ACTIVE_BIAS - RWSEM_WAITING_BIAS;
-	if (!downgrading)
-		/* we'd already done one increment earlier */
-		woken -= RWSEM_ACTIVE_BIAS;
-
-	rwsem_atomic_add(woken, sem);
-
-	next = sem->wait_list.next;
-	for (; loop > 0; loop--) {
-		waiter = list_entry(next, struct rwsem_waiter, list);
-		next = waiter->list.next;
-		tsk = waiter->task;
-		smp_mb();
-		waiter->task = NULL;
-		wake_up_process(tsk);
-		put_task_struct(tsk);
-	}
-
-	sem->wait_list.next = next;
-	next->prev = &sem->wait_list;
-
- out:
-	return sem;
-
-	/* undo the change to count, but check for a transition 1->0 */
- undo:
-	if (rwsem_atomic_update(-RWSEM_ACTIVE_BIAS, sem) != 0)
-		goto out;
-	goto try_again;
-}
-
-/*
- * wait for a lock to be granted
- */
-static struct rw_semaphore __sched *
-rwsem_down_failed_common(struct rw_semaphore *sem,
-			struct rwsem_waiter *waiter, signed long adjustment)
-{
-	struct task_struct *tsk = current;
-	signed long count;
-
-	set_task_state(tsk, TASK_UNINTERRUPTIBLE);
-
-	/* set up my own style of waitqueue */
-	spin_lock_irq(&sem->wait_lock);
-	waiter->task = tsk;
-	get_task_struct(tsk);
-
-	list_add_tail(&waiter->list, &sem->wait_list);
-
-	/* we're now waiting on the lock, but no longer actively read-locking */
-	count = rwsem_atomic_update(adjustment, sem);
-
-	/* if there are no active locks, wake the front queued process(es) up */
-	if (!(count & RWSEM_ACTIVE_MASK))
-		sem = __rwsem_do_wake(sem, 0);
-
-	spin_unlock_irq(&sem->wait_lock);
-
-	/* wait to be given the lock */
-	for (;;) {
-		if (!waiter->task)
-			break;
-		schedule();
-		set_task_state(tsk, TASK_UNINTERRUPTIBLE);
-	}
-
-	tsk->state = TASK_RUNNING;
-
-	return sem;
-}
-
-/*
- * wait for the read lock to be granted
- */
-asmregparm struct rw_semaphore __sched *
-rwsem_down_read_failed(struct rw_semaphore *sem)
-{
-	struct rwsem_waiter waiter;
-
-	waiter.flags = RWSEM_WAITING_FOR_READ;
-	rwsem_down_failed_common(sem, &waiter,
-				RWSEM_WAITING_BIAS - RWSEM_ACTIVE_BIAS);
-	return sem;
-}
-
-/*
- * wait for the write lock to be granted
- */
-asmregparm struct rw_semaphore __sched *
-rwsem_down_write_failed(struct rw_semaphore *sem)
-{
-	struct rwsem_waiter waiter;
-
-	waiter.flags = RWSEM_WAITING_FOR_WRITE;
-	rwsem_down_failed_common(sem, &waiter, -RWSEM_ACTIVE_BIAS);
-
-	return sem;
-}
-
-/*
- * handle waking up a waiter on the semaphore
- * - up_read/up_write has decremented the active part of count if we come here
- */
-asmregparm struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&sem->wait_lock, flags);
-
-	/* do nothing if list empty */
-	if (!list_empty(&sem->wait_list))
-		sem = __rwsem_do_wake(sem, 0);
-
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
-
-	return sem;
-}
-
-/*
- * downgrade a write lock into a read lock
- * - caller incremented waiting part of count and discovered it still negative
- * - just wake up any readers at the front of the queue
- */
-asmregparm struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&sem->wait_lock, flags);
-
-	/* do nothing if list empty */
-	if (!list_empty(&sem->wait_list))
-		sem = __rwsem_do_wake(sem, 1);
-
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
-
-	return sem;
-}
-
-EXPORT_SYMBOL(rwsem_down_read_failed);
-EXPORT_SYMBOL(rwsem_down_write_failed);
-EXPORT_SYMBOL(rwsem_wake);
-EXPORT_SYMBOL(rwsem_downgrade_wake);