lkml.org 
[lkml]   [2010]   [Nov]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH V3] futex: add futex_q static initializer
On Mon, 8 Nov 2010, Darren Hart wrote:

> 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.
> V3: make futex_q_init const
>
> Signed-off-by: Darren Hart <dvhart@linux.intel.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..e6df2de 100644
> --- a/kernel/futex.c
> +++ b/kernel/futex.c
> @@ -131,6 +131,12 @@ struct futex_q {
> u32 bitset;
> };
>
> +static const 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;

You sure about that one in the retry path ?

> @@ -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;

Ditto

Thanks,

tglx


\
 
 \ /
  Last update: 2010-11-08 22:51    [W:0.739 / U:0.660 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site