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x86/mce: Remove explicit smp_rmb() when starting CPUs sync 

mce_start() has an explicit smp_wmb() to serialize writes to global_nwo
and mce_callin. However, atomic_inc_return() implies barriers on both
sides of the call, as such simply rely on this full SMP barrier.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1458602396-840-1-git-send-email-dave@stgolabs.net
Link: http://lkml.kernel.org/r/1459929916-12852-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Davidlohr Bueso 2016-04-06 10:05:15 +02:00 committed by Ingo Molnar
parent 69385f8879
commit bf92b1feb6
1 changed files with 2 additions and 2 deletions
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4
arch/x86/kernel/cpu/mcheck/mce.c
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@ -830,9 +830,9 @@ static int mce_start(int *no_way_out)
atomic_add(*no_way_out, &global_nwo);
/*
* global_nwo should be updated before mce_callin
* Rely on the implied barrier below, such that global_nwo
* is updated before mce_callin.
*/
smp_wmb();
order = atomic_inc_return(&mce_callin);
/*