[tip:tracing/core] compiler: Introduce __always_unused

From: tip-bot for Li Zefan
Date: Mon Nov 02 2009 - 11:17:12 EST

Commit-ID: 7b2a35132ad0a70902dcd2844c27ed64cda0ce9b
Gitweb: http://git.kernel.org/tip/7b2a35132ad0a70902dcd2844c27ed64cda0ce9b
Author: Li Zefan <lizf@xxxxxxxxxxxxxx>
AuthorDate: Mon, 2 Nov 2009 08:50:52 +0800
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Mon, 2 Nov 2009 15:47:54 +0100

compiler: Introduce __always_unused

I wrote some code which is used as compile-time checker, and the
code should be elided after compile.

So I need to annotate the code as "always unused", compared to
"maybe unused".

Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
LKML-Reference: <4AEE2CEC.8040206@xxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
include/linux/compiler-gcc.h | 1 +
include/linux/compiler.h | 4 ++++
2 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index a3ed7cb..73dcf80 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -79,6 +79,7 @@
#define noinline __attribute__((noinline))
#define __attribute_const__ __attribute__((__const__))
#define __maybe_unused __attribute__((unused))
+#define __always_unused __attribute__((unused))

#define __gcc_header(x) #x
#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 04fb513..7947f4f 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -213,6 +213,10 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
# define __maybe_unused /* unimplemented */

+#ifndef __always_unused
+# define __always_unused /* unimplemented */
#ifndef noinline
#define noinline
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