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/drivers/parisc/eisa.c b/drivers/parisc/eisa.c
index 771cef592542..7891db50c483 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;