generic: reduce stack pressure in sched_affinity

  * Modify sched_affinity functions to pass cpumask_t variables by reference
    instead of by value.

  * Use new set_cpus_allowed_ptr function.

Depends on:
	[sched-devel]: sched: add new set_cpus_allowed_ptr function

Cc: Paul Jackson <pj@sgi.com>
Cc: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 23 insertions, 23 deletions

diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd_64.c b/arch/x86/kernel/cpu/mcheck/mce_amd_64.c
index 32671da8184..7c9a813e119 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd_64.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd_64.c
@@ -251,18 +251,18 @@ struct threshold_attr {
 	ssize_t(*store) (struct threshold_block *, const char *, size_t count);
 };
 
-static cpumask_t affinity_set(unsigned int cpu)
+static void affinity_set(unsigned int cpu, cpumask_t *oldmask,
+					   cpumask_t *newmask)
 {
-	cpumask_t oldmask = current->cpus_allowed;
-	cpumask_t newmask = CPU_MASK_NONE;
-	cpu_set(cpu, newmask);
-	set_cpus_allowed(current, newmask);
-	return oldmask;
+	*oldmask = current->cpus_allowed;
+	cpus_clear(*newmask);
+	cpu_set(cpu, *newmask);
+	set_cpus_allowed_ptr(current, newmask);
 }
 
-static void affinity_restore(cpumask_t oldmask)
+static void affinity_restore(const cpumask_t *oldmask)
 {
-	set_cpus_allowed(current, oldmask);
+	set_cpus_allowed_ptr(current, oldmask);
 }
 
 #define SHOW_FIELDS(name)                                           \
@@ -277,15 +277,15 @@ static ssize_t store_interrupt_enable(struct threshold_block *b,
 				      const char *buf, size_t count)
 {
 	char *end;
-	cpumask_t oldmask;
+	cpumask_t oldmask, newmask;
 	unsigned long new = simple_strtoul(buf, &end, 0);
 	if (end == buf)
 		return -EINVAL;
 	b->interrupt_enable = !!new;
 
-	oldmask = affinity_set(b->cpu);
+	affinity_set(b->cpu, &oldmask, &newmask);
 	threshold_restart_bank(b, 0, 0);
-	affinity_restore(oldmask);
+	affinity_restore(&oldmask);
 
 	return end - buf;
 }
@@ -294,7 +294,7 @@ static ssize_t store_threshold_limit(struct threshold_block *b,
 				     const char *buf, size_t count)
 {
 	char *end;
-	cpumask_t oldmask;
+	cpumask_t oldmask, newmask;
 	u16 old;
 	unsigned long new = simple_strtoul(buf, &end, 0);
 	if (end == buf)
@@ -306,9 +306,9 @@ static ssize_t store_threshold_limit(struct threshold_block *b,
 	old = b->threshold_limit;
 	b->threshold_limit = new;
 
-	oldmask = affinity_set(b->cpu);
+	affinity_set(b->cpu, &oldmask, &newmask);
 	threshold_restart_bank(b, 0, old);
-	affinity_restore(oldmask);
+	affinity_restore(&oldmask);
 
 	return end - buf;
 }
@@ -316,10 +316,10 @@ static ssize_t store_threshold_limit(struct threshold_block *b,
 static ssize_t show_error_count(struct threshold_block *b, char *buf)
 {
 	u32 high, low;
-	cpumask_t oldmask;
-	oldmask = affinity_set(b->cpu);
+	cpumask_t oldmask, newmask;
+	affinity_set(b->cpu, &oldmask, &newmask);
 	rdmsr(b->address, low, high);
-	affinity_restore(oldmask);
+	affinity_restore(&oldmask);
 	return sprintf(buf, "%x\n",
 		       (high & 0xFFF) - (THRESHOLD_MAX - b->threshold_limit));
 }
@@ -327,10 +327,10 @@ static ssize_t show_error_count(struct threshold_block *b, char *buf)
 static ssize_t store_error_count(struct threshold_block *b,
 				 const char *buf, size_t count)
 {
-	cpumask_t oldmask;
-	oldmask = affinity_set(b->cpu);
+	cpumask_t oldmask, newmask;
+	affinity_set(b->cpu, &oldmask, &newmask);
 	threshold_restart_bank(b, 1, 0);
-	affinity_restore(oldmask);
+	affinity_restore(&oldmask);
 	return 1;
 }
 
@@ -468,7 +468,7 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
 {
 	int i, err = 0;
 	struct threshold_bank *b = NULL;
-	cpumask_t oldmask = CPU_MASK_NONE;
+	cpumask_t oldmask, newmask;
 	char name[32];
 
 	sprintf(name, "threshold_bank%i", bank);
@@ -519,10 +519,10 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
 
 	per_cpu(threshold_banks, cpu)[bank] = b;
 
-	oldmask = affinity_set(cpu);
+	affinity_set(cpu, &oldmask, &newmask);
 	err = allocate_threshold_blocks(cpu, bank, 0,
 					MSR_IA32_MC0_MISC + bank * 4);
-	affinity_restore(oldmask);
+	affinity_restore(&oldmask);
 
 	if (err)
 		goto out_free;