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, 2 insertions, 2 deletions

diff --git a/arch/x86/mach-voyager/voyager_smp.c b/arch/x86/mach-voyager/voyager_smp.c
index 199a5f4a873c..0f6e8a6523ae 100644
--- a/arch/x86/mach-voyager/voyager_smp.c
+++ b/arch/x86/mach-voyager/voyager_smp.c
@@ -1483,7 +1483,7 @@ static void disable_local_vic_irq(unsigned int irq)
  * the interrupt off to another CPU */
 static void before_handle_vic_irq(unsigned int irq)
 {
-        irq_desc_t *desc = irq_desc + irq;
+        irq_desc_t *desc = irq_to_desc(irq);
         __u8 cpu = smp_processor_id();
 
         _raw_spin_lock(&vic_irq_lock);
@@ -1518,7 +1518,7 @@ static void before_handle_vic_irq(unsigned int irq)
 /* Finish the VIC interrupt: basically mask */
 static void after_handle_vic_irq(unsigned int irq)
 {
-        irq_desc_t *desc = irq_desc + irq;
+        irq_desc_t *desc = irq_to_desc(irq);
 
         _raw_spin_lock(&vic_irq_lock);
         {