[PATCH] x86_64/i386: Remove preempt disable calls in lowlevel IPI

I noticed that some lowlevel send_IPI_mask helpers had a hotplug/preempt
race whereupon the cpu_online_map was read before disabling preemption;

...
cpumask_t mask = cpu_online_map;
int cpu = get_cpu();
cpu_clear(cpu, mask);
...

But then i realised that there is no need for these lowlevel functions to
be going through all this trouble when all the callers are already made
hotplug/preempt safe.

Signed-off-by: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 3 deletions

diff --git a/include/asm-i386/mach-default/mach_ipi.h b/include/asm-i386/mach-default/mach_ipi.h
index cc756a67cd63..a1d0072e36bc 100644
--- a/include/asm-i386/mach-default/mach_ipi.h
+++ b/include/asm-i386/mach-default/mach_ipi.h
@@ -15,11 +15,9 @@ static inline void __local_send_IPI_allbutself(int vector)
 {
         if (no_broadcast) {
                 cpumask_t mask = cpu_online_map;
-                int this_cpu = get_cpu();
 
-                cpu_clear(this_cpu, mask);
+                cpu_clear(smp_processor_id(), mask);
                 send_IPI_mask(mask, vector);
-                put_cpu();
         } else
                 __send_IPI_shortcut(APIC_DEST_ALLBUT, vector);
 }