irq: initialize nr_irqs based on nr_cpu_ids

Impact: Reduce memory usage.

This is the second half of the changes to make the irq_desc_ptrs be
variable sized based on nr_cpu_ids.  This is done by adding a new
"max_nr_irqs" macro to irq_vectors.h (and a dummy in irqnr.h) to
return a max NR_IRQS value based on NR_CPUS or nr_cpu_ids.

This necessitated moving the define of MAX_IO_APICS to a separate
file (asm/apicnum.h) so it could be included without the baggage
of the other asm/apicdef.h declarations.

Signed-off-by: Mike Travis <travis@sgi.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/irqnr.h b/include/linux/irqnr.h
index 86af92e9e84c..de66e4e10406 100644
--- a/include/linux/irqnr.h
+++ b/include/linux/irqnr.h
@@ -20,11 +20,18 @@
 
 # define for_each_irq_desc_reverse(irq, desc)                          \
         for (irq = nr_irqs - 1; irq >= 0; irq--)
+
 #else /* CONFIG_GENERIC_HARDIRQS */
 
+#include <asm/irq_vectors.h>    /* need possible max_nr_irqs() */
+
 extern int nr_irqs;
 extern struct irq_desc *irq_to_desc(unsigned int irq);
 
+# ifndef max_nr_irqs
+#  define max_nr_irqs(nr_cpus)  NR_IRQS
+# endif
+
 # define for_each_irq_desc(irq, desc)                                   \
         for (irq = 0, desc = irq_to_desc(irq); irq < nr_irqs;           \
              irq++, desc = irq_to_desc(irq))                            \