genirq: Split irq_set_affinity() so it can be called with lock held.

The .irq_cpu_online() and .irq_cpu_offline() functions may need to
adjust affinity, but they are called with the descriptor lock held.
Create __irq_set_affinity_locked() which is called with the lock held.
Make irq_set_affinity() just a wrapper that acquires the lock.

[ tglx: Changed the argument to irq_data, added a !desc check and
        moved the !irq_set_affinity check where it belongs ]

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: ralf@linux-mips.org
LKML-Reference: <1301081931-11240-4-git-send-email-ddaney@caviumnetworks.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 31 insertions, 18 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 76e948fa88f8..a10717e1c1f3 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -382,6 +382,7 @@ extern void remove_irq(unsigned int irq, struct irqaction *act);
 
 extern void irq_cpu_online(void);
 extern void irq_cpu_offline(void);
+extern int __irq_set_affinity_locked(struct irq_data *data,  const struct cpumask *cpumask);
 
 #ifdef CONFIG_GENERIC_HARDIRQS
 
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 0a2aa73e536c..3d151fd762ad 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -139,35 +139,26 @@ static inline void
 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
 #endif
 
-/**
- *      irq_set_affinity - Set the irq affinity of a given irq
- *      @irq:           Interrupt to set affinity
- *      @cpumask:       cpumask
- *
- */
-int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
+int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
 {
-        struct irq_desc *desc = irq_to_desc(irq);
-        struct irq_chip *chip = desc->irq_data.chip;
-        unsigned long flags;
+        struct irq_chip *chip = irq_data_get_irq_chip(data);
+        struct irq_desc *desc = irq_data_to_desc(data);
         int ret = 0;
 
-        if (!chip->irq_set_affinity)
+        if (!chip || !chip->irq_set_affinity)
                 return -EINVAL;
 
-        raw_spin_lock_irqsave(&desc->lock, flags);
-
-        if (irq_can_move_pcntxt(desc)) {
-                ret = chip->irq_set_affinity(&desc->irq_data, mask, false);
+        if (irqd_can_move_in_process_context(data)) {
+                ret = chip->irq_set_affinity(data, mask, false);
                 switch (ret) {
                 case IRQ_SET_MASK_OK:
-                        cpumask_copy(desc->irq_data.affinity, mask);
+                        cpumask_copy(data->affinity, mask);
                 case IRQ_SET_MASK_OK_NOCOPY:
                         irq_set_thread_affinity(desc);
                         ret = 0;
                 }
         } else {
-                irqd_set_move_pending(&desc->irq_data);
+                irqd_set_move_pending(data);
                 irq_copy_pending(desc, mask);
         }
 
@@ -176,7 +167,28 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
                 schedule_work(&desc->affinity_notify->work);
         }
         irq_compat_set_affinity(desc);
-        irqd_set(&desc->irq_data, IRQD_AFFINITY_SET);
+        irqd_set(data, IRQD_AFFINITY_SET);
+
+        return ret;
+}
+
+/**
+ *      irq_set_affinity - Set the irq affinity of a given irq
+ *      @irq:           Interrupt to set affinity
+ *      @cpumask:       cpumask
+ *
+ */
+int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
+{
+        struct irq_desc *desc = irq_to_desc(irq);
+        unsigned long flags;
+        int ret;
+
+        if (!desc)
+                return -EINVAL;
+
+        raw_spin_lock_irqsave(&desc->lock, flags);
+        ret =  __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
         raw_spin_unlock_irqrestore(&desc->lock, flags);
         return ret;
 }