Messages in this thread Patch in this message | | | From | Darren Hart <> | Subject | [PATCH V2] futex: add futex_q static initializer | Date | Mon, 8 Nov 2010 13:12:50 -0800 |
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The futex_q struct has grown considerably over the last couple years. I believe it now merits a static initializer to avoid uninitialized data errors (having spent more time than I care to admit debugging an uninitialized q.bitset in an experimental new op code).
With the key initializer built in, several of the FUTEX_KEY_INIT calls can be removed.
V2: use a static variable instead of an init macro. use a C99 initializer and don't rely on variable ordering in the struct.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@elte.hu> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: John Kacur <jkacur@redhat.com> --- kernel/futex.c | 25 ++++++++++--------------- 1 files changed, 10 insertions(+), 15 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c index fd3fbe1..1eea066 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -131,6 +131,12 @@ struct futex_q { u32 bitset; }; +static struct futex_q futex_q_init = { + /* list gets initialized in queue_me()*/ + .key = FUTEX_KEY_INIT, + .bitset = FUTEX_BITSET_MATCH_ANY +}; + /* * Hash buckets are shared by all the futex_keys that hash to the same * location. Each key may have multiple futex_q structures, one for each task @@ -1751,7 +1757,6 @@ static int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags, * rare, but normal. */ retry: - q->key = FUTEX_KEY_INIT; ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q->key); if (unlikely(ret != 0)) return ret; @@ -1792,16 +1797,12 @@ static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, struct hrtimer_sleeper timeout, *to = NULL; struct restart_block *restart; struct futex_hash_bucket *hb; - struct futex_q q; + struct futex_q q = futex_q_init; int ret; if (!bitset) return -EINVAL; - - q.pi_state = NULL; q.bitset = bitset; - q.rt_waiter = NULL; - q.requeue_pi_key = NULL; if (abs_time) { to = &timeout; @@ -1892,7 +1893,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, int detect, { struct hrtimer_sleeper timeout, *to = NULL; struct futex_hash_bucket *hb; - struct futex_q q; + struct futex_q q = futex_q_init; int res, ret; if (refill_pi_state_cache()) @@ -1906,11 +1907,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, int detect, hrtimer_set_expires(&to->timer, *time); } - q.pi_state = NULL; - q.rt_waiter = NULL; - q.requeue_pi_key = NULL; retry: - q.key = FUTEX_KEY_INIT; ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key); if (unlikely(ret != 0)) goto out; @@ -2198,8 +2195,8 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, struct rt_mutex_waiter rt_waiter; struct rt_mutex *pi_mutex = NULL; struct futex_hash_bucket *hb; - union futex_key key2; - struct futex_q q; + union futex_key key2 = FUTEX_KEY_INIT; + struct futex_q q = futex_q_init; int res, ret; if (!bitset) @@ -2222,12 +2219,10 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, debug_rt_mutex_init_waiter(&rt_waiter); rt_waiter.task = NULL; - key2 = FUTEX_KEY_INIT; ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2); if (unlikely(ret != 0)) goto out; - q.pi_state = NULL; q.bitset = bitset; q.rt_waiter = &rt_waiter; q.requeue_pi_key = &key2; -- 1.7.1
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