locking, sched: Give waitqueue spinlocks their own lockdep classes (2fc39111) · Commits · 戴 / test

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:

Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:

David Howells <dhowells@redhat.com> Tested-by:

Takashi 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:

Ingo Molnar <mingo@elte.hu>

include/linux/wait.h

+8 −1

Original line number	Diff line number	Diff line
		@@ -77,7 +77,14 @@ struct task_struct;
		#define __WAIT_BIT_KEY_INITIALIZER(word, 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
		# define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \

kernel/wait.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -10,13 +10,14 @@
		#include <linux/wait.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);
		lockdep_set_class(&q->lock, key);
		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)
		{

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