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authorPeter Zijlstra <peterz@infradead.org>2009-08-10 12:33:05 +0100
committerIngo Molnar <mingo@elte.hu>2009-08-10 14:43:09 +0200
commit2fc391112fb6f3424435a3aa2fda887497b5f807 (patch)
tree89cda7002d591807536dca68b6344a558b081428
parentbeda2c7ea2c15ed01eef00a997d2b0496c3a502d (diff)
downloadconfigs-2fc391112fb6f3424435a3aa2fda887497b5f807.tar.gz
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: 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>
-rw-r--r--include/linux/wait.h9
-rw-r--r--kernel/wait.c5
2 files changed, 11 insertions, 3 deletions
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 6788e1a4d4c..cf3c2f5dba5 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -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) \
diff --git a/kernel/wait.c b/kernel/wait.c
index ea7c3b4275c..c4bd3d825f3 100644
--- a/kernel/wait.c
+++ b/kernel/wait.c
@@ -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)
{