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| author | David Daney <david.daney@cavium.com> | 2013-09-11 14:23:29 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-11 15:58:25 -0700 |
| commit | 202da400570d991bacda4a06e878cb901e96a783 (patch) | |
| tree | 135d76acc021c2a67b8c24dc1084b3d6cf8e01e5 /kernel | |
| parent | f9597f24c089dcbddbd2d9e99fbf00df57fb70c6 (diff) | |
| download | lwn-202da400570d991bacda4a06e878cb901e96a783.tar.gz lwn-202da400570d991bacda4a06e878cb901e96a783.zip | |
kernel/smp.c: quit unconditionally enabling irqs in on_each_cpu_mask().
As in commit f21afc25f9ed ("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>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/smp.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/kernel/smp.c b/kernel/smp.c index 3bb6ae533cdf..0564571dcdf7 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -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(); } |