generic: sparse irqs: use irq_desc() together with dyn_array, instead of irq_desc[]

add CONFIG_HAVE_SPARSE_IRQ to for use condensed array.
Get rid of irq_desc[] array assumptions.

Preallocate 32 irq_desc, and irq_desc() will try to get more.

( No change in functionality is expected anywhere, except the odd build
  failure where we missed a code site or where a crossing commit itroduces
  new irq_desc[] usage. )

v2: according to Eric, change get_irq_desc() to irq_desc()

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 20 insertions, 15 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index d5a4333d8f1f..b5943e9f95aa 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -31,7 +31,7 @@ cpumask_t irq_default_affinity = CPU_MASK_ALL;
  */
 void synchronize_irq(unsigned int irq)
 {
-	struct irq_desc *desc = irq_desc + irq;
+	struct irq_desc *desc = irq_to_desc(irq);
 	unsigned int status;
 
 	if (irq >= nr_irqs)
@@ -64,7 +64,7 @@ EXPORT_SYMBOL(synchronize_irq);
  */
 int irq_can_set_affinity(unsigned int irq)
 {
-	struct irq_desc *desc = irq_desc + irq;
+	struct irq_desc *desc = irq_to_desc(irq);
 
 	if (CHECK_IRQ_PER_CPU(desc->status) || !desc->chip ||
 	    !desc->chip->set_affinity)
@@ -81,7 +81,7 @@ int irq_can_set_affinity(unsigned int irq)
  */
 int irq_set_affinity(unsigned int irq, cpumask_t cpumask)
 {
-	struct irq_desc *desc = irq_desc + irq;
+	struct irq_desc *desc = irq_to_desc(irq);
 
 	if (!desc->chip->set_affinity)
 		return -EINVAL;
@@ -111,14 +111,16 @@ int irq_set_affinity(unsigned int irq, cpumask_t cpumask)
 int irq_select_affinity(unsigned int irq)
 {
 	cpumask_t mask;
+	struct irq_desc *desc;
 
 	if (!irq_can_set_affinity(irq))
 		return 0;
 
 	cpus_and(mask, cpu_online_map, irq_default_affinity);
 
-	irq_desc[irq].affinity = mask;
-	irq_desc[irq].chip->set_affinity(irq, mask);
+	desc = irq_to_desc(irq);
+	desc->affinity = mask;
+	desc->chip->set_affinity(irq, mask);
 
 	set_balance_irq_affinity(irq, mask);
 	return 0;
@@ -140,7 +142,7 @@ int irq_select_affinity(unsigned int irq)
  */
 void disable_irq_nosync(unsigned int irq)
 {
-	struct irq_desc *desc = irq_desc + irq;
+	struct irq_desc *desc = irq_to_desc(irq);
 	unsigned long flags;
 
 	if (irq >= nr_irqs)
@@ -169,7 +171,7 @@ EXPORT_SYMBOL(disable_irq_nosync);
  */
 void disable_irq(unsigned int irq)
 {
-	struct irq_desc *desc = irq_desc + irq;
+	struct irq_desc *desc = irq_to_desc(irq);
 
 	if (irq >= nr_irqs)
 		return;
@@ -211,7 +213,7 @@ static void __enable_irq(struct irq_desc *desc, unsigned int irq)
  */
 void enable_irq(unsigned int irq)
 {
-	struct irq_desc *desc = irq_desc + irq;
+	struct irq_desc *desc = irq_to_desc(irq);
 	unsigned long flags;
 
 	if (irq >= nr_irqs)
@@ -225,7 +227,7 @@ EXPORT_SYMBOL(enable_irq);
 
 static int set_irq_wake_real(unsigned int irq, unsigned int on)
 {
-	struct irq_desc *desc = irq_desc + irq;
+	struct irq_desc *desc = irq_to_desc(irq);
 	int ret = -ENXIO;
 
 	if (desc->chip->set_wake)
@@ -248,7 +250,7 @@ static int set_irq_wake_real(unsigned int irq, unsigned int on)
  */
 int set_irq_wake(unsigned int irq, unsigned int on)
 {
-	struct irq_desc *desc = irq_desc + irq;
+	struct irq_desc *desc = irq_to_desc(irq);
 	unsigned long flags;
 	int ret = 0;
 
@@ -288,12 +290,13 @@ EXPORT_SYMBOL(set_irq_wake);
  */
 int can_request_irq(unsigned int irq, unsigned long irqflags)
 {
+	struct irq_desc *desc = irq_to_desc(irq);
 	struct irqaction *action;
 
-	if (irq >= nr_irqs || irq_desc[irq].status & IRQ_NOREQUEST)
+	if (irq >= nr_irqs || desc->status & IRQ_NOREQUEST)
 		return 0;
 
-	action = irq_desc[irq].action;
+	action = desc->action;
 	if (action)
 		if (irqflags & action->flags & IRQF_SHARED)
 			action = NULL;
@@ -349,7 +352,7 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
  */
 int setup_irq(unsigned int irq, struct irqaction *new)
 {
-	struct irq_desc *desc = irq_desc + irq;
+	struct irq_desc *desc = irq_to_desc(irq);
 	struct irqaction *old, **p;
 	const char *old_name = NULL;
 	unsigned long flags;
@@ -518,7 +521,7 @@ void free_irq(unsigned int irq, void *dev_id)
 	if (irq >= nr_irqs)
 		return;
 
-	desc = irq_desc + irq;
+	desc = irq_to_desc(irq);
 	spin_lock_irqsave(&desc->lock, flags);
 	p = &desc->action;
 	for (;;) {
@@ -615,6 +618,7 @@ int request_irq(unsigned int irq, irq_handler_t handler,
 {
 	struct irqaction *action;
 	int retval;
+	struct irq_desc *desc;
 
 #ifdef CONFIG_LOCKDEP
 	/*
@@ -632,7 +636,8 @@ int request_irq(unsigned int irq, irq_handler_t handler,
 		return -EINVAL;
 	if (irq >= nr_irqs)
 		return -EINVAL;
-	if (irq_desc[irq].status & IRQ_NOREQUEST)
+	desc = irq_to_desc(irq);
+	if (desc->status & IRQ_NOREQUEST)
 		return -EINVAL;
 	if (!handler)
 		return -EINVAL;