[PATCH 4.18 054/197] x86/mce: Add notifier_block forward declaration

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@xxxxxxxx>

[ Upstream commit 704ae091b061082b37a9968621af4c290c641d50 ]

Without linux/irq.h, there is no declaration of notifier_block, leading to
a build warning:

In file included from arch/x86/kernel/cpu/mcheck/threshold.c:10:
arch/x86/include/asm/mce.h:151:46: error: 'struct notifier_block' declared inside parameter list will not be visible outside of this definition or declaration [-Werror]

It's sufficient to declare the struct tag here, which avoids pulling in
more header files.

Fixes: 447ae3166702 ("x86: Don't include linux/irq.h from asm/hardirq.h")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Nicolai Stange <nstange@xxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Link: https://lkml.kernel.org/r/20180817100156.3009043-1-arnd@xxxxxxxx
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/mce.h |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -148,6 +148,7 @@ enum mce_notifier_prios {
 	MCE_PRIO_LOWEST		= 0,
 };
 
+struct notifier_block;
 extern void mce_register_decode_chain(struct notifier_block *nb);
 extern void mce_unregister_decode_chain(struct notifier_block *nb);