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

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As in commit f21afc25f9 ("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>
This commit is contained in:
David Daney 2013-09-11 14:23:29 -07:00 committed by Linus Torvalds
parent f9597f24c0
commit 202da40057
1 changed files with 7 additions and 4 deletions
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11
kernel/smp.c
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@ -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();
}