From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932876Ab1LFD2J (ORCPT ); Mon, 5 Dec 2011 22:28:09 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:44921 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932859Ab1LFD2H (ORCPT ); Mon, 5 Dec 2011 22:28:07 -0500 Date: Tue, 6 Dec 2011 11:27:54 +0800 From: Yong Zhang To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, patches@linaro.org Subject: [PATCH 1/3] kernel.h: sched: introduce might_sleep_disabled() Message-ID: <20111206032754.GA17091@zhy> Reply-To: Yong Zhang References: <20111203183417.GA18914@linux.vnet.ibm.com> <1322937282-19846-7-git-send-email-paulmck@linux.vnet.ibm.com> <20111205091924.GA28117@zhy> <20111205164505.GB2326@linux.vnet.ibm.com> <20111206012635.GA32498@zhy> <20111206021227.GO2326@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20111206021227.GO2326@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since commit [5342e269: rcu: Permit rt_mutex_unlock() with irqs disabled], rt_mutex_lock() could be called with irqs disabled and it will call might_sleep() unconditionally. To prevent this kind of false positive, introduce might_sleep_disabled() which will be used in later patch. Signed-off-by: Yong Zhang --- include/linux/kernel.h | 25 +++++++++++++++++++++---- include/linux/sched.h | 14 +++++++------- kernel/sched.c | 6 ++++-- 3 files changed, 32 insertions(+), 13 deletions(-) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index e8b1597..deaba68 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -130,7 +130,8 @@ extern int _cond_resched(void); #endif #ifdef CONFIG_DEBUG_ATOMIC_SLEEP - void __might_sleep(const char *file, int line, int preempt_offset); + void __might_sleep(const char *file, int line, int preempt_offset, + bool warn_irqs); /** * might_sleep - annotation for functions that can sleep * @@ -141,12 +142,28 @@ extern int _cond_resched(void); * be bitten later when the calling function happens to sleep when it is not * supposed to. */ -# define might_sleep() \ - do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0) +# define might_sleep() \ + do { \ + __might_sleep(__FILE__, __LINE__, 0, true); \ + might_resched(); } \ + while (0) + +/* + * Special version of might_sleep() which don't warn when called + * with irq disabled. Will be used in rt_mutex_lock() which + * could be called with irq disabled. + */ +# define might_sleep_irqdisabled() \ + do { \ + __might_sleep(__FILE__, __LINE__, 0, false); \ + might_resched(); } \ + while (0) + #else static inline void __might_sleep(const char *file, int line, - int preempt_offset) { } + int preempt_offset, bool warn_irqs) { } # define might_sleep() do { might_resched(); } while (0) +# define might_sleep_irqdisabled() do { might_resched(); } while (0) #endif #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) diff --git a/include/linux/sched.h b/include/linux/sched.h index 4a7e4d3..d077c62 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2534,9 +2534,9 @@ static inline int need_resched(void) */ extern int _cond_resched(void); -#define cond_resched() ({ \ - __might_sleep(__FILE__, __LINE__, 0); \ - _cond_resched(); \ +#define cond_resched() ({ \ + __might_sleep(__FILE__, __LINE__, 0, true); \ + _cond_resched(); \ }) extern int __cond_resched_lock(spinlock_t *lock); @@ -2547,15 +2547,15 @@ extern int __cond_resched_lock(spinlock_t *lock); #define PREEMPT_LOCK_OFFSET 0 #endif -#define cond_resched_lock(lock) ({ \ - __might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET); \ - __cond_resched_lock(lock); \ +#define cond_resched_lock(lock) ({ \ + __might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET, true); \ + __cond_resched_lock(lock); \ }) extern int __cond_resched_softirq(void); #define cond_resched_softirq() ({ \ - __might_sleep(__FILE__, __LINE__, SOFTIRQ_DISABLE_OFFSET); \ + __might_sleep(__FILE__, __LINE__, SOFTIRQ_DISABLE_OFFSET, true);\ __cond_resched_softirq(); \ }) diff --git a/kernel/sched.c b/kernel/sched.c index 0e9344a..ce24450 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8363,12 +8363,14 @@ static inline int preempt_count_equals(int preempt_offset) return (nested == preempt_offset); } -void __might_sleep(const char *file, int line, int preempt_offset) +void __might_sleep(const char *file, int line, int preempt_offset, + bool warn_irqs) { static unsigned long prev_jiffy; /* ratelimiting */ rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ - if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || + if ((preempt_count_equals(preempt_offset) && + (warn_irqs ? !irqs_disabled() : 1)) || system_state != SYSTEM_RUNNING || oops_in_progress) return; if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) -- 1.7.5.4