[tip:x86/apic] x86/apic: Get rid of "warning: 'acpi_ioapic_lock' defined but not used"

[tip-bot for Sebastian Andrzej Siewior]

Commit-ID:  d2d9c4a3d01c20f936f88e0c2793945e6632dab6
Gitweb:     http://git.kernel.org/tip/d2d9c4a3d01c20f936f88e0c2793945e6632dab6
Author:     Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate: Fri, 21 Oct 2016 10:44:49 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 21 Oct 2016 11:09:14 +0200

x86/apic: Get rid of "warning: 'acpi_ioapic_lock' defined but not used"

kbuild test robot reported this against the -RT tree:

|>> arch/x86/kernel/acpi/boot.c:90:21: warning: 'acpi_ioapic_lock' defined but not used [-Wunused-variable]
|    static DEFINE_MUTEX(acpi_ioapic_lock);
|                        ^
|   include/linux/mutex_rt.h:27:15: note: in definition of macro 'DEFINE_MUTEX'
|     struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
                  ^~~~~~~~~
which is also true (as in non-used) for !RT but the compiler does not
emit a warning.

Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20161021084449.32523-1-bigeasy@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/kernel/acpi/boot.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 8a5abaa..066ceb7 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -76,6 +76,7 @@ int acpi_fix_pin2_polarity __initdata;
 static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
 #endif
 
+#ifdef CONFIG_X86_IO_APIC
 /*
  * Locks related to IOAPIC hotplug
  * Hotplug side:
@@ -88,6 +89,7 @@ static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
  *			->ioapic_lock
  */
 static DEFINE_MUTEX(acpi_ioapic_lock);
+#endif
 
 /* --------------------------------------------------------------------------
                               Boot-time Configuration