Prev: [PATCH 1/4] rtmutex: avoid null derefence in WARN_ON
Next: [PATCH 4/4] futex: convert hash_bucket locks to raw_spinlock_t
From: Darren Hart on 9 Jul 2010 18:40
free_pi_state() calls kfree() and might sleep. To prepare for raw hb->locks,
get the calls to free_pi_state() out of the hb->lock() sections.

Signed-off-by: Darren Hart <dvhltc(a)us.ibm.com>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Ingo Molnar <mingo(a)elte.hu>
Cc: Eric Dumazet <eric.dumazet(a)gmail.com>
Cc: John Kacur <jkacur(a)redhat.com>
Cc: Steven Rostedt <rostedt(a)goodmis.org>
Cc: Mike Galbraith <efault(a)gmx.de>
---
kernel/futex.c | 14 ++++++++------
1 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index a6cec32..b217972 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -114,7 +114,7 @@ struct futex_q {
struct plist_node list;

struct task_struct *task;
- spinlock_t *lock_ptr;
+ raw_spinlock_t *lock_ptr;
union futex_key key;
struct futex_pi_state *pi_state;
struct rt_mutex_waiter *rt_waiter;
@@ -487,7 +487,7 @@ void exit_pi_state_list(struct task_struct *curr)
* task still owns the PI-state:
*/
if (head->next != next) {
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
continue;
}

@@ -1339,7 +1339,6 @@ retry_private:
} else if (ret) {
/* -EDEADLK */
this->pi_state = NULL;
- free_pi_state(pi_state);
goto out_unlock;
}
}
@@ -1437,7 +1436,7 @@ static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb)
*/
static int unqueue_me(struct futex_q *q)
{
- spinlock_t *lock_ptr;
+ raw_spinlock_t *lock_ptr;
int ret = 0;

/* In the common case we don't take the spinlock, which is nice. */
@@ -1483,16 +1482,19 @@ retry:
*/
static void unqueue_me_pi(struct futex_q *q)
{
+ struct futex_pi_state *pi_state = NULL;
+
WARN_ON(plist_node_empty(&q->list));
plist_del(&q->list, &q->list.plist);

BUG_ON(!q->pi_state);
- free_pi_state(q->pi_state);
+ pi_state = q->pi_state;
q->pi_state = NULL;

spin_unlock(q->lock_ptr);
-
drop_futex_key_refs(&q->key);
+
+ free_pi_state(pi_state);
}

/*
--
1.7.0.4

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Next: [PATCH 4/4] futex: convert hash_bucket locks to raw_spinlock_t