x86 smp: modify send_IPI_mask interface to accept cpumask_t pointers

Impact: cleanup, change parameter passing

  * Change genapic interfaces to accept cpumask_t pointers where possible.

  * Modify external callers to use cpumask_t pointers in function calls.

  * Create new send_IPI_mask_allbutself which is the same as the
    send_IPI_mask functions but removes smp_processor_id() from list.
    This removes another common need for a temporary cpumask_t variable.

  * Functions that used a temp cpumask_t variable for:

	cpumask_t allbutme = cpu_online_map;

	cpu_clear(smp_processor_id(), allbutme);
	if (!cpus_empty(allbutme))
		...

    become:

	if (!cpus_equal(cpu_online_map, cpumask_of_cpu(cpu)))
		...

  * Other minor code optimizations (like using cpus_clear instead of
    CPU_MASK_NONE, etc.)

Applies to linux-2.6.tip/master.

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Ingo Molnar <mingo@elte.hu>

arch/x86/mach-generic/summit.c

@@ -24,7 +24,7 @@ static int probe_summit(void)
 	return 0;
 }
 
-static cpumask_t vector_allocation_domain(int cpu)
+static void vector_allocation_domain(int cpu, cpumask_t *retmask)
 {
 	/* Careful. Some cpus do not strictly honor the set of cpus
 	 * specified in the interrupt destination when using lowest
@@ -34,8 +34,7 @@ static cpumask_t vector_allocation_domain(int cpu)
 	 * deliver interrupts to the wrong hyperthread when only one
 	 * hyperthread was specified in the interrupt desitination.
 	 */
-	cpumask_t domain = { { [0] = APIC_ALL_CPUS, } };
-	return domain;
+	*retmask = (cpumask_t){ { [0] = APIC_ALL_CPUS, } };
 }
 
 struct genapic apic_summit = APIC_INIT("summit", probe_summit);