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Subject[PATCH 1/8 v2] x86, UV: smp_processor_id in a preemptable region
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From: Cliff Wickman <cpw@sgi.com>

Calling smp_processor_id() from within a preemptable region will issue
a warning if DEBUG_PREEMPT is set.

Which cpu is returned by smp_processor_id() is actually arbitrary here, as
every cpu has a per-cpu structure with the needed limit for the tunable. But
the call should be non-preemptable to avoid a warning in a DEBUG_PREEMPT
kernel.

Diffed against 3.0.0-rc3

Signed-off-by: Cliff Wickman <cpw@sgi.com>
---
arch/x86/platform/uv/tlb_uv.c | 2 ++
1 file changed, 2 insertions(+)

Index: linux/arch/x86/platform/uv/tlb_uv.c
===================================================================
--- linux.orig/arch/x86/platform/uv/tlb_uv.c
+++ linux/arch/x86/platform/uv/tlb_uv.c
@@ -1334,7 +1334,9 @@ static ssize_t tunables_write(struct fil

instr[count] = '\0';

+ preempt_disable(); /* avoid DEBUG_PREEMPT warning */
bcp = &per_cpu(bau_control, smp_processor_id());
+ preempt_enable_no_resched();

ret = parse_tunables_write(bcp, instr, count);
if (ret)

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