cpumask: convert kernel/irq

Impact: Reduce stack usage, use new cpumask API.  ALPHA mod!

Main change is that irq_default_affinity becomes a cpumask_var_t, so
treat it as a pointer (this effects alpha).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

4 files changed, 33 insertions, 15 deletions

diff --git a/arch/alpha/kernel/irq.c b/arch/alpha/kernel/irq.c
index d0f1620007f7..703731accda6 100644
--- a/arch/alpha/kernel/irq.c
+++ b/arch/alpha/kernel/irq.c
@@ -50,7 +50,8 @@ int irq_select_affinity(unsigned int irq)
         if (!irq_desc[irq].chip->set_affinity || irq_user_affinity[irq])
                 return 1;
 
-        while (!cpu_possible(cpu) || !cpu_isset(cpu, irq_default_affinity))
+        while (!cpu_possible(cpu) ||
+               !cpumask_test_cpu(cpu, irq_default_affinity))
                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
         last_cpu = cpu;
 
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index dfaee6bd265b..91f1ef8e5810 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -109,7 +109,7 @@ extern void enable_irq(unsigned int irq);
 
 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
 
-extern cpumask_t irq_default_affinity;
+extern cpumask_var_t irq_default_affinity;
 
 extern int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask);
 extern int irq_can_set_affinity(unsigned int irq);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 61c4a9b62165..cd0cd8dcb345 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -16,8 +16,15 @@
 #include "internals.h"
 
 #ifdef CONFIG_SMP
+cpumask_var_t irq_default_affinity;
 
-cpumask_t irq_default_affinity = CPU_MASK_ALL;
+static int init_irq_default_affinity(void)
+{
+        alloc_cpumask_var(&irq_default_affinity, GFP_KERNEL);
+        cpumask_setall(irq_default_affinity);
+        return 0;
+}
+core_initcall(init_irq_default_affinity);
 
 /**
  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
@@ -127,7 +134,7 @@ int do_irq_select_affinity(unsigned int irq, struct irq_desc *desc)
                         desc->status &= ~IRQ_AFFINITY_SET;
         }
 
-        cpumask_and(&desc->affinity, cpu_online_mask, &irq_default_affinity);
+        cpumask_and(&desc->affinity, cpu_online_mask, irq_default_affinity);
 set_affinity:
         desc->chip->set_affinity(irq, &desc->affinity);
 
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index d2c0e5ee53c5..2abd3a7716ed 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -20,7 +20,7 @@ static struct proc_dir_entry *root_irq_dir;
 static int irq_affinity_proc_show(struct seq_file *m, void *v)
 {
         struct irq_desc *desc = irq_to_desc((long)m->private);
-        cpumask_t *mask = &desc->affinity;
+        const struct cpumask *mask = &desc->affinity;
 
 #ifdef CONFIG_GENERIC_PENDING_IRQ
         if (desc->status & IRQ_MOVE_PENDING)
@@ -93,7 +93,7 @@ static const struct file_operations irq_affinity_proc_fops = {
 
 static int default_affinity_show(struct seq_file *m, void *v)
 {
-        seq_cpumask(m, &irq_default_affinity);
+        seq_cpumask(m, irq_default_affinity);
         seq_putc(m, '\n');
         return 0;
 }
@@ -101,27 +101,37 @@ static int default_affinity_show(struct seq_file *m, void *v)
 static ssize_t default_affinity_write(struct file *file,
                 const char __user *buffer, size_t count, loff_t *ppos)
 {
-        cpumask_t new_value;
+        cpumask_var_t new_value;
         int err;
 
-        err = cpumask_parse_user(buffer, count, &new_value);
+        if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
+                return -ENOMEM;
+
+        err = cpumask_parse_user(buffer, count, new_value);
         if (err)
-                return err;
+                goto out;
 
-        if (!is_affinity_mask_valid(new_value))
-                return -EINVAL;
+        if (!is_affinity_mask_valid(new_value)) {
+                err = -EINVAL;
+                goto out;
+        }
 
         /*
          * Do not allow disabling IRQs completely - it's a too easy
          * way to make the system unusable accidentally :-) At least
          * one online CPU still has to be targeted.
          */
-        if (!cpus_intersects(new_value, cpu_online_map))
-                return -EINVAL;
+        if (!cpumask_intersects(new_value, cpu_online_mask)) {
+                err = -EINVAL;
+                goto out;
+        }
 
-        irq_default_affinity = new_value;
+        cpumask_copy(irq_default_affinity, new_value);
+        err = count;
 
-        return count;
+out:
+        free_cpumask_var(new_value);
+        return err;
 }
 
 static int default_affinity_open(struct inode *inode, struct file *file)