[patch] io-apic cleanup #3, BK-curr

[Ingo Molnar <mingo@elte.hu>]

the patch below gets rid of io_apic_sync().

io_apic_sync() was introduced in 2.1.104 and it was originally done for
masking and unmasking as well. Later the unmasking use got removed but
the masking use lingered around. I dont think it was ever justified to
do it and clearly since the lack of io_apic_sync() didnt break some of
the other writes we do to the IO-APIC registers, it must be unnecessary
in the masking case too. Maciej?

	Ingo

Signed-off-by: Ingo Molnar <mingo@elte.hu>

--- linux/arch/i386/kernel/io_apic.c.orig	
+++ linux/arch/i386/kernel/io_apic.c	
@@ -145,10 +145,7 @@ static void __modify_IO_APIC_irq (unsign
 /* mask = 1 */
 static void __mask_IO_APIC_irq (unsigned int irq)
 {
-	struct irq_pin_list *entry = irq_2_pin + irq;
 	__modify_IO_APIC_irq(irq, 0x00010000, 0);
-	/* Is it needed? Or do others need it too? */
-	io_apic_sync(entry->apic);
 }
 
 /* mask = 0 */
--- linux/include/asm-i386/io_apic.h.orig	
+++ linux/include/asm-i386/io_apic.h	
@@ -188,15 +188,6 @@ static inline void io_apic_modify(unsign
 	*(IO_APIC_BASE(apic)+4) = value;
 }
 
-/*
- * Synchronize the IO-APIC and the CPU by doing
- * a dummy read from the IO-APIC
- */
-static inline void io_apic_sync(unsigned int apic)
-{
-	(void) *(IO_APIC_BASE(apic)+4);
-}
-
 /* 1 if "noapic" boot option passed */
 extern int skip_ioapic_setup;