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>

2 files changed, 3 insertions, 3 deletions

diff --git a/drivers/mfd/asic3.c b/drivers/mfd/asic3.c
index ba5aa2008273..e4c0db4dc7b1 100644
--- a/drivers/mfd/asic3.c
+++ b/drivers/mfd/asic3.c
@@ -123,7 +123,7 @@ static void asic3_irq_demux(unsigned int irq, struct irq_desc *desc)
                                         irqnr = asic->irq_base +
                                                 (ASIC3_GPIOS_PER_BANK * bank)
                                                 + i;
-                                        desc = irq_desc + irqnr;
+                                        desc = irq_to_desc(irqnr);
                                         desc->handle_irq(irqnr, desc);
                                         if (asic->irq_bothedge[bank] & bit)
                                                 asic3_irq_flip_edge(asic, base,
@@ -136,7 +136,7 @@ static void asic3_irq_demux(unsigned int irq, struct irq_desc *desc)
                 for (i = ASIC3_NUM_GPIOS; i < ASIC3_NR_IRQS; i++) {
                         /* They start at bit 4 and go up */
                         if (status & (1 << (i - ASIC3_NUM_GPIOS + 4))) {
-                                desc = irq_desc + asic->irq_base + i;
+                                desc = irq_to_desc(asic->irq_base + i);
                                 desc->handle_irq(asic->irq_base + i,
                                                  desc);
                         }
diff --git a/drivers/mfd/htc-egpio.c b/drivers/mfd/htc-egpio.c
index 6be43172dc65..ad3379fcd194 100644
--- a/drivers/mfd/htc-egpio.c
+++ b/drivers/mfd/htc-egpio.c
@@ -112,7 +112,7 @@ static void egpio_handler(unsigned int irq, struct irq_desc *desc)
                 /* Run irq handler */
                 pr_debug("got IRQ %d\n", irqpin);
                 irq = ei->irq_start + irqpin;
-                desc = &irq_desc[irq];
+                desc = irq_to_desc(irq);
                 desc->handle_irq(irq, desc);
         }
 }