Eric Lee / linux-smarc-t335x-v3.2

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Commit 2fc391112fb6f3424435a3aa2fda887497b5f807

Authored by Peter Zijlstra
Committed by Ingo Molnar
1 parent beda2c7ea2

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>

Showing 2 changed files with 11 additions and 3 deletions Side-by-side Diff

include/linux/wait.h
Diff comments   View file @ 2fc3911
... ... @@ -77,7 +77,14 @@
77 77 #define __WAIT_BIT_KEY_INITIALIZER(word, bit) \
78 78 { .flags = word, .bit_nr = bit, }
79 79  
80   -extern void init_waitqueue_head(wait_queue_head_t *q);
  80 +extern void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *);
  81 +
  82 +#define init_waitqueue_head(q) \
  83 + do { \
  84 + static struct lock_class_key __key; \
  85 + \
  86 + __init_waitqueue_head((q), &__key); \
  87 + } while (0)
81 88  
82 89 #ifdef CONFIG_LOCKDEP
83 90 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
... ... @@ -10,13 +10,14 @@
10 10 #include <linux/wait.h>
11 11 #include <linux/hash.h>
12 12  
13   -void init_waitqueue_head(wait_queue_head_t *q)
  13 +void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *key)
14 14 {
15 15 spin_lock_init(&q->lock);
  16 + lockdep_set_class(&q->lock, key);
16 17 INIT_LIST_HEAD(&q->task_list);
17 18 }
18 19  
19   -EXPORT_SYMBOL(init_waitqueue_head);
  20 +EXPORT_SYMBOL(__init_waitqueue_head);
20 21  
21 22 void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)
22 23 {