x86/ioapic.c: simplify add_pin_to_irq_node()

Rather than duplicating the same alloc/init code twice, restructure
the function to look for duplicates and then add an entry
if none is found.

This function is not performance critical; all but one of its callers
are __init functions, and the non-__init caller is for PCI device setup.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 8 insertions, 20 deletions

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 0d0401802d4f..d9e8f19088d4 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -490,34 +490,22 @@ static void ioapic_mask_entry(int apic, int pin)
  */
 static void add_pin_to_irq_node(struct irq_cfg *cfg, int node, int apic, int pin)
 {
-        struct irq_pin_list *entry;
+        struct irq_pin_list **entryp, *entry;
 
-        entry = cfg->irq_2_pin;
-        if (!entry) {
-                entry = get_one_free_irq_2_pin(node);
-                if (!entry) {
-                        printk(KERN_ERR "can not alloc irq_2_pin to add %d - %d\n",
-                                        apic, pin);
-                        return;
-                }
-                cfg->irq_2_pin = entry;
-                entry->apic = apic;
-                entry->pin = pin;
-                return;
-        }
-
-        while (entry->next) {
+        for (entryp = &cfg->irq_2_pin;
+             *entryp != NULL;
+             entryp = &(*entryp)->next) {
+                entry = *entryp;
                 /* not again, please */
                 if (entry->apic == apic && entry->pin == pin)
                         return;
-
-                entry = entry->next;
         }
 
-        entry->next = get_one_free_irq_2_pin(node);
-        entry = entry->next;
+        entry = get_one_free_irq_2_pin(node);
         entry->apic = apic;
         entry->pin = pin;
+
+        *entryp = entry;
 }
 
 /*