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, 3 insertions, 1 deletions

diff --git a/drivers/parisc/iosapic.c b/drivers/parisc/iosapic.c
index 6fb3f7979f21..7beffcab2745 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)