Commit 00b30cf0 authored Jun 21, 2011 by cpw@sgi.com Committed by Ingo Molnar Jun 21, 2011

x86, UV: Fix smp_processor_id() use in a preemptable region



Fix a call by tunables_write() to smp_processor_id() within a
preemptable region.

Call get_cpu()/put_cpu() around the region where the returned
cpu number is actually used, which makes it non-preemptable.

A DEBUG_PREEMPT warning is prevented.

UV does not support cpu hotplug yet, but this is a step toward
that ability as well.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Link: http://lkml.kernel.org/r/20110621122242.086384966@sgi.com


Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 68856859

arch/x86/platform/uv/tlb_uv.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -1334,9 +1334,10 @@ static ssize_t tunables_write(struct file file, const char __user user,

		instr[count] = '\0';

		bcp = &per_cpu(bau_control, smp_processor_id());

		cpu = get_cpu();
		bcp = &per_cpu(bau_control, cpu);
		ret = parse_tunables_write(bcp, instr, count);
		put_cpu();
		if (ret)
		return ret;