Commit 0f476b6d authored by Johannes Berg's avatar Johannes Berg Committed by Ingo Molnar
Browse files

softirq: remove irqs_disabled warning from local_bh_enable 



There's no need to use local_irq_save() over local_irq_disable() in the
local_bh_enable code since it is a bug to call it with irqs disabled and
do_softirq will enable irqs if there is any pending work.

Consolidate the code from local_bh_enable and ..._ip to avoid having a
disconnect between them in the warnings they trigger that is currently
there.

Also always trigger the warning on in_irq(), not just in the
trace-irqflags case.

Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Cc: Michael Buesch <mb@bu3sch.de>
Cc: David Ellingsworth <david@identd.dyndns.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 4620b49f

kernel/softirq.c

+11 −37
Original line number Diff line number Diff line
@@ -131,23 +131,17 @@ void _local_bh_enable(void) 


EXPORT_SYMBOL(_local_bh_enable);



void local_bh_enable(void)

static inline void _local_bh_enable_ip(unsigned long ip)

{

	WARN_ON_ONCE(in_irq() || irqs_disabled());

#ifdef CONFIG_TRACE_IRQFLAGS

	unsigned long flags;



	WARN_ON_ONCE(in_irq());

#endif

	WARN_ON_ONCE(irqs_disabled());



#ifdef CONFIG_TRACE_IRQFLAGS

	local_irq_save(flags);

	local_irq_disable();

#endif

	/*

	 * Are softirqs going to be turned on now:

	 */

	if (softirq_count() == SOFTIRQ_OFFSET)

		trace_softirqs_on((unsigned long)__builtin_return_address(0));

		trace_softirqs_on(ip);

	/*

	 * Keep preemption disabled until we are done with

	 * softirq processing:
@@ -159,40 +153,20 @@ void local_bh_enable(void) 


	dec_preempt_count();

#ifdef CONFIG_TRACE_IRQFLAGS

	local_irq_restore(flags);

	local_irq_enable();

#endif

	preempt_check_resched();

}



void local_bh_enable(void)

{

	_local_bh_enable_ip((unsigned long)__builtin_return_address(0));

}

EXPORT_SYMBOL(local_bh_enable);



void local_bh_enable_ip(unsigned long ip)

{

#ifdef CONFIG_TRACE_IRQFLAGS

	unsigned long flags;



	WARN_ON_ONCE(in_irq());



	local_irq_save(flags);

#endif

	/*

	 * Are softirqs going to be turned on now:

	 */

	if (softirq_count() == SOFTIRQ_OFFSET)

		trace_softirqs_on(ip);

	/*

	 * Keep preemption disabled until we are done with

	 * softirq processing:

 	 */

 	sub_preempt_count(SOFTIRQ_OFFSET - 1);



	if (unlikely(!in_interrupt() && local_softirq_pending()))

		do_softirq();



	dec_preempt_count();

#ifdef CONFIG_TRACE_IRQFLAGS

	local_irq_restore(flags);

#endif

	preempt_check_resched();

	_local_bh_enable_ip(ip);

}

EXPORT_SYMBOL(local_bh_enable_ip);

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