x86, UV: Remove cpumask_t from the stack

Remove the large stack-resident cpumask_t from
reset_with_ipi()'s stack by allocating one per uvhub.

Due to the limited size of the stack the potentially huge cpumask_t may
cause stack overrun.  We haven't seen it happen yet, but we need to make it
a practice not to push such structures onto the stack.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20110621122242.832589130@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/include/asm/uv/uv_bau.h b/arch/x86/include/asm/uv/uv_bau.h
index fa6a48e..16ce58c 100644
--- a/arch/x86/include/asm/uv/uv_bau.h
+++ b/arch/x86/include/asm/uv/uv_bau.h
@@ -488,6 +488,7 @@
 	struct bau_control	*uvhub_master;
 	struct bau_control	*socket_master;
 	struct ptc_stats	*statp;
+	cpumask_t		*cpumask;
 	unsigned long		timeout_interval;
 	unsigned long		set_bau_on_time;
 	atomic_t		active_descriptor_count;