From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755511AbaFUUe7 (ORCPT ); Sat, 21 Jun 2014 16:34:59 -0400 Received: from terminus.zytor.com ([198.137.202.10]:34877 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755295AbaFUUe5 (ORCPT ); Sat, 21 Jun 2014 16:34:57 -0400 Date: Sat, 21 Jun 2014 13:33:55 -0700 From: tip-bot for Thomas Gleixner Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, peterz@infradead.org, darren@dvhart.com, kees@outflux.net, tglx@linutronix.de, davidlohr@hp.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, darren@dvhart.com, peterz@infradead.org, kees@outflux.net, tglx@linutronix.de, davidlohr@hp.com In-Reply-To: <20140611204237.271300614@linutronix.de> References: <20140611204237.271300614@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:locking/core] futex: Split out the first waiter attachment from lookup_pi_state() Git-Commit-ID: 04e1b2e52b17195c9a1daa5935c55a4c8716095c X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 04e1b2e52b17195c9a1daa5935c55a4c8716095c Gitweb: http://git.kernel.org/tip/04e1b2e52b17195c9a1daa5935c55a4c8716095c Author: Thomas Gleixner AuthorDate: Wed, 11 Jun 2014 20:45:40 +0000 Committer: Thomas Gleixner CommitDate: Sat, 21 Jun 2014 22:26:23 +0200 futex: Split out the first waiter attachment from lookup_pi_state() We want to be a bit more clever in futex_lock_pi_atomic() and separate the possible states. Split out the code which attaches the first waiter to the owner into a separate function. No functional change. Signed-off-by: Thomas Gleixner Reviewed-by: Darren Hart Cc: Peter Zijlstra Cc: Davidlohr Bueso Cc: Kees Cook Cc: wad@chromium.org Link: http://lkml.kernel.org/r/20140611204237.271300614@linutronix.de Signed-off-by: Thomas Gleixner --- kernel/futex.c | 42 ++++++++++++++++++++++++++++-------------- 1 file changed, 28 insertions(+), 14 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index db0c686..e65b686 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -865,21 +865,16 @@ out_state: return 0; } -static int -lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, - union futex_key *key, struct futex_pi_state **ps) +/* + * Lookup the task for the TID provided from user space and attach to + * it after doing proper sanity checks. + */ +static int attach_to_pi_owner(u32 uval, union futex_key *key, + struct futex_pi_state **ps) { - struct futex_q *match = futex_top_waiter(hb, key); - struct futex_pi_state *pi_state = NULL; - struct task_struct *p; pid_t pid = uval & FUTEX_TID_MASK; - - /* - * If there is a waiter on that futex, validate it and - * attach to the pi_state when the validation succeeds. - */ - if (match) - return attach_to_pi_state(uval, match->pi_state, ps); + struct futex_pi_state *pi_state; + struct task_struct *p; /* * We are the first waiter - try to look up the real owner and attach @@ -922,7 +917,7 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, pi_state = alloc_pi_state(); /* - * Initialize the pi_mutex in locked state and make 'p' + * Initialize the pi_mutex in locked state and make @p * the owner of it: */ rt_mutex_init_proxy_locked(&pi_state->pi_mutex, p); @@ -942,6 +937,25 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, return 0; } +static int lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, + union futex_key *key, struct futex_pi_state **ps) +{ + struct futex_q *match = futex_top_waiter(hb, key); + + /* + * If there is a waiter on that futex, validate it and + * attach to the pi_state when the validation succeeds. + */ + if (match) + return attach_to_pi_state(uval, match->pi_state, ps); + + /* + * We are the first waiter - try to look up the owner based on + * @uval and attach to it. + */ + return attach_to_pi_owner(uval, key, ps); +} + /** * futex_lock_pi_atomic() - Atomic work required to acquire a pi aware futex * @uaddr: the pi futex user address