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>

5 files changed, 20 insertions, 10 deletions

diff --git a/drivers/parisc/dino.c b/drivers/parisc/dino.c
index fd56128525d..3bc54b30c3a 100644
--- a/drivers/parisc/dino.c
+++ b/drivers/parisc/dino.c
@@ -298,7 +298,8 @@ struct pci_port_ops dino_port_ops = {
 
 static void dino_disable_irq(unsigned int irq)
 {
-	struct dino_device *dino_dev = irq_desc[irq].chip_data;
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct dino_device *dino_dev = desc->chip_data;
 	int local_irq = gsc_find_local_irq(irq, dino_dev->global_irq, DINO_LOCAL_IRQS);
 
 	DBG(KERN_WARNING "%s(0x%p, %d)\n", __func__, dino_dev, irq);
@@ -310,7 +311,8 @@ static void dino_disable_irq(unsigned int irq)
 
 static void dino_enable_irq(unsigned int irq)
 {
-	struct dino_device *dino_dev = irq_desc[irq].chip_data;
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct dino_device *dino_dev = desc->chip_data;
 	int local_irq = gsc_find_local_irq(irq, dino_dev->global_irq, DINO_LOCAL_IRQS);
 	u32 tmp;
 
diff --git a/drivers/parisc/eisa.c b/drivers/parisc/eisa.c
index 771cef59254..7891db50c48 100644
--- a/drivers/parisc/eisa.c
+++ b/drivers/parisc/eisa.c
@@ -346,10 +346,10 @@ static int __init eisa_probe(struct parisc_device *dev)
 	}
 	
 	/* Reserve IRQ2 */
-	irq_desc[2].action = &irq2_action;
+	irq_to_desc(2)->action = &irq2_action;
 	
 	for (i = 0; i < 16; i++) {
-		irq_desc[i].chip = &eisa_interrupt_type;
+		irq_to_desc(i)->chip = &eisa_interrupt_type;
 	}
 	
 	EISA_bus = 1;
diff --git a/drivers/parisc/gsc.c b/drivers/parisc/gsc.c
index f7d088b897e..e76db9e4d50 100644
--- a/drivers/parisc/gsc.c
+++ b/drivers/parisc/gsc.c
@@ -108,7 +108,8 @@ int gsc_find_local_irq(unsigned int irq, int *global_irqs, int limit)
 
 static void gsc_asic_disable_irq(unsigned int irq)
 {
-	struct gsc_asic *irq_dev = irq_desc[irq].chip_data;
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct gsc_asic *irq_dev = desc->chip_data;
 	int local_irq = gsc_find_local_irq(irq, irq_dev->global_irq, 32);
 	u32 imr;
 
@@ -123,7 +124,8 @@ static void gsc_asic_disable_irq(unsigned int irq)
 
 static void gsc_asic_enable_irq(unsigned int irq)
 {
-	struct gsc_asic *irq_dev = irq_desc[irq].chip_data;
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct gsc_asic *irq_dev = desc->chip_data;
 	int local_irq = gsc_find_local_irq(irq, irq_dev->global_irq, 32);
 	u32 imr;
 
@@ -159,12 +161,14 @@ static struct hw_interrupt_type gsc_asic_interrupt_type = {
 int gsc_assign_irq(struct hw_interrupt_type *type, void *data)
 {
 	static int irq = GSC_IRQ_BASE;
+	struct irq_desc *desc;
 
 	if (irq > GSC_IRQ_MAX)
 		return NO_IRQ;
 
-	irq_desc[irq].chip = type;
-	irq_desc[irq].chip_data = data;
+	desc = irq_to_desc(irq);
+	desc->chip = type;
+	desc->chip_data = data;
 	return irq++;
 }
 
diff --git a/drivers/parisc/iosapic.c b/drivers/parisc/iosapic.c
index 6fb3f7979f2..7beffcab274 100644
--- a/drivers/parisc/iosapic.c
+++ b/drivers/parisc/iosapic.c
@@ -619,7 +619,9 @@ iosapic_set_irt_data( struct vector_info *vi, u32 *dp0, u32 *dp1)
 
 static struct vector_info *iosapic_get_vector(unsigned int irq)
 {
-	return irq_desc[irq].chip_data;
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	return desc->chip_data;
 }
 
 static void iosapic_disable_irq(unsigned int irq)
diff --git a/drivers/parisc/superio.c b/drivers/parisc/superio.c
index 1e8d2d17f04..1e93c837514 100644
--- a/drivers/parisc/superio.c
+++ b/drivers/parisc/superio.c
@@ -363,7 +363,9 @@ int superio_fixup_irq(struct pci_dev *pcidev)
 #endif
 
 	for (i = 0; i < 16; i++) {
-		irq_desc[i].chip = &superio_interrupt_type;
+		struct irq_desc *desc = irq_to_desc(i);
+
+		desc->chip = &superio_interrupt_type;
 	}
 
 	/*