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, 9 insertions, 3 deletions

diff --git a/drivers/pcmcia/hd64465_ss.c b/drivers/pcmcia/hd64465_ss.c
index 117dc12ab438..9ef69cdb3183 100644
--- a/drivers/pcmcia/hd64465_ss.c
+++ b/drivers/pcmcia/hd64465_ss.c
@@ -233,15 +233,18 @@ static struct hw_interrupt_type hd64465_ss_irq_type = {
  */
 static void hs_map_irq(hs_socket_t *sp, unsigned int irq)
 {
+        struct irq_desc *desc;
+
         DPRINTK("hs_map_irq(sock=%d irq=%d)\n", sp->number, irq);
         
         if (irq >= HS_NUM_MAPPED_IRQS)
             return;
 
+        desc = irq_to_desc(irq);
         hs_mapped_irq[irq].sock = sp;
         /* insert ourselves as the irq controller */
-        hs_mapped_irq[irq].old_handler = irq_desc[irq].chip;
-        irq_desc[irq].chip = &hd64465_ss_irq_type;
+        hs_mapped_irq[irq].old_handler = desc->chip;
+        desc->chip = &hd64465_ss_irq_type;
 }
 
 
@@ -250,13 +253,16 @@ static void hs_map_irq(hs_socket_t *sp, unsigned int irq)
  */
 static void hs_unmap_irq(hs_socket_t *sp, unsigned int irq)
 {
+        struct irq_desc *desc;
+
         DPRINTK("hs_unmap_irq(sock=%d irq=%d)\n", sp->number, irq);
         
         if (irq >= HS_NUM_MAPPED_IRQS)
             return;
                 
+        desc = irq_to_desc(irq);
         /* restore the original irq controller */
-        irq_desc[irq].chip = hs_mapped_irq[irq].old_handler;
+        desc->chip = hs_mapped_irq[irq].old_handler;
 }
 
 /*============================================================*/