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>

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
 

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;
 }