From: Baoquan He <bhe@redhat.com>
Date: Wed, 14 Feb 2018 13:46:51 +0800
Subject: x86/apic: Split out restore_boot_irq_mode() from disable_IO_APIC()
Git-commit: ce279cdc04aafd5c41ae49f941ee2c3342e35e3e
Patch-mainline: v4.17-rc1
References: bsc#1110006

This is a preparation patch. Split out the code which restores boot
irq mode from disable_IO_APIC() into the new restore_boot_irq_mode()
function.

No functional changes.

Signed-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: douly.fnst@cn.fujitsu.com
Cc: joro@8bytes.org
Cc: prarit@redhat.com
Cc: uobergfe@redhat.com
Link: http://lkml.kernel.org/r/20180214054656.3780-2-bhe@redhat.com
[ Build fix for !CONFIG_IO_APIC and rewrote the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
 arch/x86/include/asm/io_apic.h | 2 ++
 arch/x86/kernel/apic/io_apic.c | 5 +++++
 2 files changed, 7 insertions(+)

--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -192,6 +192,7 @@ static inline unsigned int io_apic_read(
 extern void setup_IO_APIC(void);
 extern void enable_IO_APIC(void);
 extern void disable_IO_APIC(void);
+extern void restore_boot_irq_mode(void);
 extern void setup_ioapic_dest(void);
 extern int IO_APIC_get_PCI_irq_vector(int bus, int devfn, int pin);
 extern void print_IO_APICs(void);
@@ -232,6 +233,7 @@ static inline void io_apic_init_mappings
 
 static inline void setup_IO_APIC(void) { }
 static inline void enable_IO_APIC(void) { }
+static inline void restore_boot_irq_mode(void) { }
 static inline void setup_ioapic_dest(void) { }
 
 #endif
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1468,6 +1468,11 @@ void disable_IO_APIC(void)
 	 */
 	clear_IO_APIC();
 
+	restore_boot_irq_mode();
+}
+
+void restore_boot_irq_mode(void)
+{
 	if (!nr_legacy_irqs())
 		return;