Commit 202da400 authored Sep 11, 2013 by David Daney Committed by Linus Torvalds Sep 11, 2013

kernel/smp.c: quit unconditionally enabling irqs in on_each_cpu_mask().



As in commit f21afc25 ("smp.h: Use local_irq_{save,restore}() in
!SMP version of on_each_cpu()"), we don't want to enable irqs if they
are not already enabled.

I don't know of any bugs currently caused by this unconditional
local_irq_enable(), but I want to use this function in MIPS/OCTEON early
boot (when we have early_boot_irqs_disabled).  This also makes this
function have similar semantics to on_each_cpu() which is good in
itself.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent f9597f24

kernel/smp.c

+7 −4

Original line number	Diff line number	Diff line
		@@ -575,8 +575,10 @@ EXPORT_SYMBOL(on_each_cpu);
		*
		* If @wait is true, then returns once @func has returned.
		*
		* You must not call this function with disabled interrupts or
		* from a hardware interrupt handler or from a bottom half handler.
		* You must not call this function with disabled interrupts or from a
		* hardware interrupt handler or from a bottom half handler. The
		* exception is that it may be used during early boot while
		* early_boot_irqs_disabled is set.
		*/
		void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
		void *info, bool wait)
		@@ -585,9 +587,10 @@ void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,

		smp_call_function_many(mask, func, info, wait);
		if (cpumask_test_cpu(cpu, mask)) {
		local_irq_disable();
		unsigned long flags;
		local_irq_save(flags);
		func(info);
		local_irq_enable();
		local_irq_restore(flags);
		}
		put_cpu();
		}