[tip:x86/urgent] x86/irqflags: Provide a declaration for native_save_fl

[tip-bot for Nick Desaulniers <tipbot@zytor.com>]

Commit-ID:  208cbb32558907f68b3b2a081ca2337ac3744794
Gitweb:     https://git.kernel.org/tip/208cbb32558907f68b3b2a081ca2337ac3744794
Author:     Nick Desaulniers <ndesaulniers@google.com>
AuthorDate: Fri, 3 Aug 2018 10:05:50 -0700
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 5 Aug 2018 22:30:37 +0200

x86/irqflags: Provide a declaration for native_save_fl

It was reported that the commit d0a8d9378d16 is causing users of gcc < 4.9
to observe -Werror=missing-prototypes errors.

Indeed, it seems that:
extern inline unsigned long native_save_fl(void) { return 0; }

compiled with -Werror=missing-prototypes produces this warning in gcc <
4.9, but not gcc >= 4.9.

Fixes: d0a8d9378d16 ("x86/paravirt: Make native_save_fl() extern inline").
Reported-by: David Laight <david.laight@aculab.com>
Reported-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@zytor.com
Cc: jgross@suse.com
Cc: kstewart@linuxfoundation.org
Cc: gregkh@linuxfoundation.org
Cc: boris.ostrovsky@oracle.com
Cc: astrachan@google.com
Cc: mka@chromium.org
Cc: arnd@arndb.de
Cc: tstellar@redhat.com
Cc: sedat.dilek@gmail.com
Cc: David.Laight@aculab.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180803170550.164688-1-ndesaulniers@google.com

---
 arch/x86/include/asm/irqflags.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index c4fc17220df9..c14f2a74b2be 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -13,6 +13,8 @@
  * Interrupt control:
  */
 
+/* Declaration required for gcc < 4.9 to prevent -Werror=missing-prototypes */
+extern inline unsigned long native_save_fl(void);
 extern inline unsigned long native_save_fl(void)
 {
 	unsigned long flags;