[PATCH] genirq MSI fixes

This is a fixed up and cleaned up replacement for genirq-msi-fixes.patch,
which should solve the i386 4KSTACKS problem.  I also added Ben's idea of
pushing the __do_IRQ() check into generic_handle_irq().

I booted this with MSI enabled, but i only have MSI devices, not MSI-X
devices.  I'd still expect MSI-X to work now.

irqchip migration helper: call __do_IRQ() if a descriptor is attached to an
irqtype-style controller.  This also fixes MSI-X IRQ handling on i386 and
x86_64.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c
index 3336cef9605a..16b491703967 100644
--- a/arch/i386/kernel/irq.c
+++ b/arch/i386/kernel/irq.c
@@ -82,6 +82,10 @@ fastcall unsigned int do_IRQ(struct pt_regs *regs)
         }
 #endif
 
+        if (!irq_desc[irq].handle_irq) {
+                __do_IRQ(irq, regs);
+                goto out_exit;
+        }
 #ifdef CONFIG_4KSTACKS
 
         curctx = (union irq_ctx *) current_thread_info();
@@ -121,6 +125,7 @@ fastcall unsigned int do_IRQ(struct pt_regs *regs)
 #endif
                 __do_IRQ(irq, regs);
 
+out_exit:
         irq_exit();
 
         return 1;