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Commit 2fc39111 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

locking, sched: Give waitqueue spinlocks their own lockdep classes 



Give waitqueue spinlocks their own lockdep classes when they
are initialised from init_waitqueue_head().  This means that
struct wait_queue::func functions can operate other waitqueues.

This is used by CacheFiles to catch the page from a backing fs
being unlocked and to wake up another thread to take a copy of
it.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Tested-by: default avatarTakashi Iwai <tiwai@suse.de>
Cc: linux-cachefs@redhat.com
Cc: torvalds@osdl.org
Cc: akpm@linux-foundation.org
LKML-Reference: <20090810113305.17284.81508.stgit@warthog.procyon.org.uk>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent beda2c7e

include/linux/wait.h

+8 −1
Original line number Original line Diff line number Diff line
@@ -77,7 +77,14 @@ struct task_struct; 
#define __WAIT_BIT_KEY_INITIALIZER(word, bit)				\

#define __WAIT_BIT_KEY_INITIALIZER(word, bit)				\

	{ .flags = word, .bit_nr = bit, }

	{ .flags = word, .bit_nr = bit, }





extern void init_waitqueue_head(wait_queue_head_t *q);

extern void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *);



#define init_waitqueue_head(q)				\

	do {						\

		static struct lock_class_key __key;	\

							\

		__init_waitqueue_head((q), &__key);	\

	} while (0)





#ifdef CONFIG_LOCKDEP

#ifdef CONFIG_LOCKDEP

# define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \

# define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \

kernel/wait.c

+3 −2
Original line number Original line Diff line number Diff line
@@ -10,13 +10,14 @@ 
#include <linux/wait.h>

#include <linux/wait.h>

#include <linux/hash.h>

#include <linux/hash.h>





void init_waitqueue_head(wait_queue_head_t *q)

void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *key)

{

{

	spin_lock_init(&q->lock);

	spin_lock_init(&q->lock);

	lockdep_set_class(&q->lock, key);

	INIT_LIST_HEAD(&q->task_list);

	INIT_LIST_HEAD(&q->task_list);

}

}





EXPORT_SYMBOL(init_waitqueue_head);

EXPORT_SYMBOL(__init_waitqueue_head);





void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)

void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)

{

{