locking: Move the rwsem code to kernel/locking/

Notably: changed lib/rwsem* targets from lib- to obj-, no idea about
the ramifications of that.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-g0kynfh5feriwc6p3h6kpbw6@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 0 insertions, 296 deletions

diff --git a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c
deleted file mode 100644
index 9be8a91..0000000
--- a/lib/rwsem-spinlock.c
+++ /dev/null
@@ -1,296 +0,0 @@
-/* rwsem-spinlock.c: R/W semaphores: contention handling functions for
- * generic spinlock implementation
- *
- * Copyright (c) 2001   David Howells (dhowells@redhat.com).
- * - Derived partially from idea by Andrea Arcangeli <andrea@suse.de>
- * - Derived also from comments by Linus
- */
-#include <linux/rwsem.h>
-#include <linux/sched.h>
-#include <linux/export.h>
-
-enum rwsem_waiter_type {
-	RWSEM_WAITING_FOR_WRITE,
-	RWSEM_WAITING_FOR_READ
-};
-
-struct rwsem_waiter {
-	struct list_head list;
-	struct task_struct *task;
-	enum rwsem_waiter_type type;
-};
-
-int rwsem_is_locked(struct rw_semaphore *sem)
-{
-	int ret = 1;
-	unsigned long flags;
-
-	if (raw_spin_trylock_irqsave(&sem->wait_lock, flags)) {
-		ret = (sem->activity != 0);
-		raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-	}
-	return ret;
-}
-EXPORT_SYMBOL(rwsem_is_locked);
-
-/*
- * initialise the semaphore
- */
-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->activity = 0;
-	raw_spin_lock_init(&sem->wait_lock);
-	INIT_LIST_HEAD(&sem->wait_list);
-}
-EXPORT_SYMBOL(__init_rwsem);
-
-/*
- * handle the lock release when processes blocked on it that can now run
- * - if we come here, then:
- *   - the 'active count' _reached_ zero
- *   - the 'waiting count' is non-zero
- * - 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 wakewrite is non-zero
- */
-static inline struct rw_semaphore *
-__rwsem_do_wake(struct rw_semaphore *sem, int wakewrite)
-{
-	struct rwsem_waiter *waiter;
-	struct task_struct *tsk;
-	int woken;
-
-	waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
-
-	if (waiter->type == RWSEM_WAITING_FOR_WRITE) {
-		if (wakewrite)
-			/* Wake up a writer. Note that we do not grant it the
-			 * lock - it will have to acquire it when it runs. */
-			wake_up_process(waiter->task);
-		goto out;
-	}
-
-	/* grant an infinite number of read locks to the front of the queue */
-	woken = 0;
-	do {
-		struct list_head *next = waiter->list.next;
-
-		list_del(&waiter->list);
-		tsk = waiter->task;
-		smp_mb();
-		waiter->task = NULL;
-		wake_up_process(tsk);
-		put_task_struct(tsk);
-		woken++;
-		if (next == &sem->wait_list)
-			break;
-		waiter = list_entry(next, struct rwsem_waiter, list);
-	} while (waiter->type != RWSEM_WAITING_FOR_WRITE);
-
-	sem->activity += woken;
-
- out:
-	return sem;
-}
-
-/*
- * wake a single writer
- */
-static inline struct rw_semaphore *
-__rwsem_wake_one_writer(struct rw_semaphore *sem)
-{
-	struct rwsem_waiter *waiter;
-
-	waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
-	wake_up_process(waiter->task);
-
-	return sem;
-}
-
-/*
- * get a read lock on the semaphore
- */
-void __sched __down_read(struct rw_semaphore *sem)
-{
-	struct rwsem_waiter waiter;
-	struct task_struct *tsk;
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
-	if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
-		/* granted */
-		sem->activity++;
-		raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-		goto out;
-	}
-
-	tsk = current;
-	set_task_state(tsk, TASK_UNINTERRUPTIBLE);
-
-	/* set up my own style of waitqueue */
-	waiter.task = tsk;
-	waiter.type = RWSEM_WAITING_FOR_READ;
-	get_task_struct(tsk);
-
-	list_add_tail(&waiter.list, &sem->wait_list);
-
-	/* we don't need to touch the semaphore struct anymore */
-	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-
-	/* wait to be given the lock */
-	for (;;) {
-		if (!waiter.task)
-			break;
-		schedule();
-		set_task_state(tsk, TASK_UNINTERRUPTIBLE);
-	}
-
-	tsk->state = TASK_RUNNING;
- out:
-	;
-}
-
-/*
- * trylock for reading -- returns 1 if successful, 0 if contention
- */
-int __down_read_trylock(struct rw_semaphore *sem)
-{
-	unsigned long flags;
-	int ret = 0;
-
-
-	raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
-	if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
-		/* granted */
-		sem->activity++;
-		ret = 1;
-	}
-
-	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-
-	return ret;
-}
-
-/*
- * get a write lock on the semaphore
- */
-void __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
-{
-	struct rwsem_waiter waiter;
-	struct task_struct *tsk;
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
-	/* set up my own style of waitqueue */
-	tsk = current;
-	waiter.task = tsk;
-	waiter.type = RWSEM_WAITING_FOR_WRITE;
-	list_add_tail(&waiter.list, &sem->wait_list);
-
-	/* wait for someone to release the lock */
-	for (;;) {
-		/*
-		 * That is the key to support write lock stealing: allows the
-		 * task already on CPU to get the lock soon rather than put
-		 * itself into sleep and waiting for system woke it or someone
-		 * else in the head of the wait list up.
-		 */
-		if (sem->activity == 0)
-			break;
-		set_task_state(tsk, TASK_UNINTERRUPTIBLE);
-		raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-		schedule();
-		raw_spin_lock_irqsave(&sem->wait_lock, flags);
-	}
-	/* got the lock */
-	sem->activity = -1;
-	list_del(&waiter.list);
-
-	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
-void __sched __down_write(struct rw_semaphore *sem)
-{
-	__down_write_nested(sem, 0);
-}
-
-/*
- * trylock for writing -- returns 1 if successful, 0 if contention
- */
-int __down_write_trylock(struct rw_semaphore *sem)
-{
-	unsigned long flags;
-	int ret = 0;
-
-	raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
-	if (sem->activity == 0) {
-		/* got the lock */
-		sem->activity = -1;
-		ret = 1;
-	}
-
-	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-
-	return ret;
-}
-
-/*
- * release a read lock on the semaphore
- */
-void __up_read(struct rw_semaphore *sem)
-{
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
-	if (--sem->activity == 0 && !list_empty(&sem->wait_list))
-		sem = __rwsem_wake_one_writer(sem);
-
-	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
-/*
- * release a write lock on the semaphore
- */
-void __up_write(struct rw_semaphore *sem)
-{
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
-	sem->activity = 0;
-	if (!list_empty(&sem->wait_list))
-		sem = __rwsem_do_wake(sem, 1);
-
-	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
-/*
- * downgrade a write lock into a read lock
- * - just wake up any readers at the front of the queue
- */
-void __downgrade_write(struct rw_semaphore *sem)
-{
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
-	sem->activity = 1;
-	if (!list_empty(&sem->wait_list))
-		sem = __rwsem_do_wake(sem, 0);
-
-	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-