1 files changed, 55 insertions, 4 deletions

diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index c2f2ccb0549a..6c6d35d68ee9 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -44,7 +44,7 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
                                    unsigned long count, void *data)
 {
         unsigned int irq = (int)(long)data, full_count = count, err;
-        cpumask_t new_value, tmp;
+        cpumask_t new_value;
 
         if (!irq_desc[irq].chip->set_affinity || no_irq_affinity ||
             irq_balancing_disabled(irq))
@@ -62,17 +62,51 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
          * way to make the system unusable accidentally :-) At least
          * one online CPU still has to be targeted.
          */
-        cpus_and(tmp, new_value, cpu_online_map);
-        if (cpus_empty(tmp))
+        if (!cpus_intersects(new_value, cpu_online_map))
                 /* Special case for empty set - allow the architecture
                    code to set default SMP affinity. */
-                return select_smp_affinity(irq) ? -EINVAL : full_count;
+                return irq_select_affinity(irq) ? -EINVAL : full_count;
 
         irq_set_affinity(irq, new_value);
 
         return full_count;
 }
 
+static int default_affinity_read(char *page, char **start, off_t off,
+                                  int count, int *eof, void *data)
+{
+        int len = cpumask_scnprintf(page, count, irq_default_affinity);
+        if (count - len < 2)
+                return -EINVAL;
+        len += sprintf(page + len, "\n");
+        return len;
+}
+
+static int default_affinity_write(struct file *file, const char __user *buffer,
+                                   unsigned long count, void *data)
+{
+        unsigned int full_count = count, err;
+        cpumask_t new_value;
+
+        err = cpumask_parse_user(buffer, count, new_value);
+        if (err)
+                return err;
+
+        if (!is_affinity_mask_valid(new_value))
+                return -EINVAL;
+
+        /*
+         * 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;
+
+        irq_default_affinity = new_value;
+
+        return full_count;
+}
 #endif
 
 static int irq_spurious_read(char *page, char **start, off_t off,
@@ -171,6 +205,21 @@ void unregister_handler_proc(unsigned int irq, struct irqaction *action)
                 remove_proc_entry(action->dir->name, irq_desc[irq].dir);
 }
 
+void register_default_affinity_proc(void)
+{
+#ifdef CONFIG_SMP
+        struct proc_dir_entry *entry;
+
+        /* create /proc/irq/default_smp_affinity */
+        entry = create_proc_entry("default_smp_affinity", 0600, root_irq_dir);
+        if (entry) {
+                entry->data = NULL;
+                entry->read_proc  = default_affinity_read;
+                entry->write_proc = default_affinity_write;
+        }
+#endif
+}
+
 void init_irq_proc(void)
 {
         int i;
@@ -180,6 +229,8 @@ void init_irq_proc(void)
         if (!root_irq_dir)
                 return;
 
+        register_default_affinity_proc();
+
         /*
          * Create entries for all existing IRQs.
          */