x86: avoid redundant loop in io_apic_level_ack_pending()

If one can find an ack pending pin, there is no need to check
the rest of them.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index 65b6840..cd01f3a 100644 (file)
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -167,11 +167,10 @@ static inline void io_apic_modify(unsigned int apic, unsigned int value)
        writel(value, &io_apic->data);
 }
 
-static int io_apic_level_ack_pending(unsigned int irq)
+static bool io_apic_level_ack_pending(unsigned int irq)
 {
        struct irq_pin_list *entry;
        unsigned long flags;
-       int pending = 0;
 
        spin_lock_irqsave(&ioapic_lock, flags);
        entry = irq_2_pin + irq;
@@ -184,13 +183,17 @@ static int io_apic_level_ack_pending(unsigned int irq)
                        break;
                reg = io_apic_read(entry->apic, 0x10 + pin*2);
                /* Is the remote IRR bit set? */
-               pending |= (reg >> 14) & 1;
+               if ((reg >> 14) & 1) {
+                       spin_unlock_irqrestore(&ioapic_lock, flags);
+                       return true;
+               }
                if (!entry->next)
                        break;
                entry = irq_2_pin + entry->next;
        }
        spin_unlock_irqrestore(&ioapic_lock, flags);
-       return pending;
+
+       return false;
 }
 
 /*