[PATCH 3.12 55/64] x86: vvar, fix excessive gcc-6 DECLARE_VVAR warnings

From: Jiri Slaby
Date: Thu Feb 11 2016 - 09:00:41 EST


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

===============

On 3.12, with gcc-6, I see a lot of:
arch/x86/include/asm/vvar.h:33:28: warning: âvvaraddr_jiffiesâ defined but not used [-Wunused-const-variable]
static type const * const vvaraddr_ ## name = \
^
arch/x86/include/asm/vvar.h:46:1: note: in expansion of macro âDECLARE_VVARâ
DECLARE_VVAR(0, volatile unsigned long, jiffies)
^~~~~~~~~~~~

In upstream, this is fixed by ef721987ae (x86, vdso: Introduce VVAR
marco for vdso32) and f40c330091 (x86, vdso: Move the vvar and hpet
mappings next to the 64-bit vDSO). But this is not applicable to
stable.

So mark the vvar declaration as __maybe_unused and be done with it.
This will generate it to the code only if it is used. I.e. the same as
with gcc < 6.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
---
arch/x86/include/asm/vvar.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index d76ac40da206..9fb01a91c013 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -30,7 +30,7 @@
#else

#define DECLARE_VVAR(offset, type, name) \
- static type const * const vvaraddr_ ## name = \
+ static type const * const vvaraddr_ ## name __maybe_unused = \
(void *)(VVAR_ADDRESS + (offset));

#define DEFINE_VVAR(type, name) \
--
2.7.1