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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
	efault@gmx.de, Arne Jansen <lists@die-jansens.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: [PATCH 2/3] printk, lockdep: Remove lockdep_off() usage
Date: Thu, 09 Jun 2011 15:06:49 +0200	[thread overview]
Message-ID: <20110609131307.539373927@chello.nl> (raw)
In-Reply-To: 20110609130647.937204592@chello.nl

[-- Attachment #1: printk-remove-lockdep_off.patch --]
[-- Type: text/plain, Size: 1661 bytes --]

Remove the lockdep_off() usage from printk(). Also add a
debug_locks_off() call to zap_locks() since that'll mess up the lock
state in a royal way anyway. Further switch to local_irq_ ops so that
the irq state is properly tracked (raw_local_irq_* isn't tracked by
lockdep, causing confusion). Also drop superfluous preempt_disable(),
disabling IRQs already avoids scheduling.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 kernel/printk.c |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

Index: linux-2.6/kernel/printk.c
===================================================================
--- linux-2.6.orig/kernel/printk.c
+++ linux-2.6/kernel/printk.c
@@ -686,6 +686,7 @@ static void zap_locks(void)
 
 	oops_timestamp = jiffies;
 
+	debug_locks_off();
 	/* If a crash is occurring, make sure we can't deadlock */
 	spin_lock_init(&logbuf_lock);
 	/* And make sure that we print immediately */
@@ -838,9 +839,8 @@ asmlinkage int vprintk(const char *fmt,
 	boot_delay_msec();
 	printk_delay();
 
-	preempt_disable();
 	/* This stops the holder of console_sem just where we want him */
-	raw_local_irq_save(flags);
+	local_irq_save(flags);
 	this_cpu = smp_processor_id();
 
 	/*
@@ -861,7 +861,6 @@ asmlinkage int vprintk(const char *fmt,
 		zap_locks();
 	}
 
-	lockdep_off();
 	spin_lock(&logbuf_lock);
 	printk_cpu = this_cpu;
 
@@ -958,11 +957,9 @@ asmlinkage int vprintk(const char *fmt,
 	if (console_trylock_for_printk(this_cpu))
 		console_unlock();
 
-	lockdep_on();
 out_restore_irqs:
-	raw_local_irq_restore(flags);
+	local_irq_restore(flags);
 
-	preempt_enable();
 	return printed_len;
 }
 EXPORT_SYMBOL(printk);



  parent reply	other threads:[~2011-06-09 13:14 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-09 13:06 [PATCH 0/3] printk: Remove lockdep_off() and wakeups Peter Zijlstra
2011-06-09 13:06 ` [PATCH 1/3] printk: Release console_sem after logbuf_lock Peter Zijlstra
2011-06-09 20:06   ` Andrew Morton
2011-06-09 20:27     ` Ingo Molnar
2011-06-09 20:54       ` Peter Zijlstra
2011-06-09 21:07         ` Andrew Morton
2011-06-09 23:57           ` Hugh Dickins
2011-06-10  0:08             ` Andrew Morton
2011-06-10  9:33               ` Ingo Molnar
2011-06-10  9:40                 ` Peter Zijlstra
2011-06-10  9:42                   ` Peter Zijlstra
2011-06-10 11:28             ` Peter Zijlstra
2011-06-10 12:30               ` Peter Zijlstra
2011-06-10 12:34                 ` Ingo Molnar
2011-06-10 12:41                   ` Peter Zijlstra
2011-06-10 12:42                     ` Peter Zijlstra
2011-06-23 19:03                 ` Pavel Machek
2011-06-10  9:30         ` Ingo Molnar
2011-06-10 10:15   ` Peter Zijlstra
2011-06-09 13:06 ` Peter Zijlstra [this message]
2011-06-10 13:23   ` [PATCH 2/3] printk, lockdep: Remove lockdep_off() usage Peter Zijlstra
2011-06-09 13:06 ` [PATCH 3/3] printk: Avoid all wakeups from printk Peter Zijlstra
2011-06-09 13:32   ` Ingo Molnar
2011-06-09 13:40     ` Peter Zijlstra
2011-06-09 13:55       ` Ingo Molnar
2011-06-09 14:06         ` Peter Zijlstra
2011-06-09 14:19           ` Ingo Molnar
2011-06-09 14:23             ` Peter Zijlstra
2011-06-09 15:47               ` Linus Torvalds
2011-06-09 15:51                 ` Ingo Molnar
2011-06-09 16:25                   ` Peter Zijlstra

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