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[PATCH] lockdep: annotate futex

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Teach special (recursive) locking code to the lock validator.  Introduces
double_lock_hb() to unify double- hash-bucket-lock taking.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ingo Molnar 2006-07-03 00:25:05 -07:00 committed by Linus Torvalds
parent f2eace23e9
commit 8b8f319fc7
1 changed files with 18 additions and 10 deletions
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28
kernel/futex.c
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@ -606,6 +606,22 @@ static int unlock_futex_pi(u32 __user *uaddr, u32 uval)
return 0;
}
/*
* Express the locking dependencies for lockdep:
*/
static inline void
double_lock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
{
if (hb1 <= hb2) {
spin_lock(&hb1->lock);
if (hb1 < hb2)
spin_lock_nested(&hb2->lock, SINGLE_DEPTH_NESTING);
} else { /* hb1 > hb2 */
spin_lock(&hb2->lock);
spin_lock_nested(&hb1->lock, SINGLE_DEPTH_NESTING);
}
}
/*
* Wake up all waiters hashed on the physical page that is mapped
* to this virtual address:
@ -674,11 +690,7 @@ retryfull:
hb2 = hash_futex(&key2);
retry:
if (hb1 < hb2)
spin_lock(&hb1->lock);
spin_lock(&hb2->lock);
if (hb1 > hb2)
spin_lock(&hb1->lock);
double_lock_hb(hb1, hb2);
op_ret = futex_atomic_op_inuser(op, uaddr2);
if (unlikely(op_ret < 0)) {
@ -787,11 +799,7 @@ static int futex_requeue(u32 __user *uaddr1, u32 __user *uaddr2,
hb1 = hash_futex(&key1);
hb2 = hash_futex(&key2);
if (hb1 < hb2)
spin_lock(&hb1->lock);
spin_lock(&hb2->lock);
if (hb1 > hb2)
spin_lock(&hb1->lock);
double_lock_hb(hb1, hb2);
if (likely(cmpval != NULL)) {
u32 curval;