i386: introduce "used_vectors" bitmap which can be used to reserve vectors.

This simplifies the io_apic.c __assign_irq_vector() logic and removes
the explicit SYSCALL_VECTOR check, and also allows for vectors to be
reserved by other mechanisms (ie. lguest).

[ tglx: arch/x86 adaptation ]

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/x86/kernel/i8259_32.c b/arch/x86/kernel/i8259_32.c
index d34a10cc13a7..f634fc715c99 100644
--- a/arch/x86/kernel/i8259_32.c
+++ b/arch/x86/kernel/i8259_32.c
@@ -403,7 +403,8 @@ void __init native_init_IRQ(void)
                 int vector = FIRST_EXTERNAL_VECTOR + i;
                 if (i >= NR_IRQS)
                         break;
-                if (vector != SYSCALL_VECTOR) 
+                /* SYSCALL_VECTOR was reserved in trap_init. */
+                if (!test_bit(vector, used_vectors))
                         set_intr_gate(vector, interrupt[i]);
         }