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From:   Rasmus Villemoes <linux@rasmusvillemoes.dk>
To:     x86@kernel.org, linux-kernel@vger.kernel.org
Cc:     Ingo Molnar <mingo@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        "H. Peter Anvin" <hpa@zytor.com>, Nadav Amit <namit@vmware.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
        ndesaulniers@google.com,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: [PATCH v2 3/6] compiler_types.h: don't #define __inline
Date:   Sat, 31 Aug 2019 01:15:24 +0200
Message-Id: <20190830231527.22304-4-linux@rasmusvillemoes.dk>
In-Reply-To: <20190830231527.22304-1-linux@rasmusvillemoes.dk>
References: <20190829083233.24162-1-linux@rasmusvillemoes.dk>
 <20190830231527.22304-1-linux@rasmusvillemoes.dk>
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The spellings __inline and __inline__ should be reserved for uses
where one really wants to refer to the inline keyword, regardless of
whether or not the spelling "inline" has been #defined to something
else. Due to use of __inline__ in uapi headers, we can't easily get
rid of the definition of __inline__. However, almost all users of
__inline has been converted to inline, so we can get rid of that
#define.

The exception is include/acpi/platform/acintel.h. However, that header
is only included when using the intel compiler (does anybody actually
build the kernel with that?), and the ACPI_INLINE macro is only used
in the definition of utterly trivial stub functions, where I doubt a
small change of semantics (lack of __gnu_inline) changes anything.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 include/linux/compiler_types.h | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 599c27b56c29..ee49be6d6088 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -150,8 +150,17 @@ struct ftrace_likely_data {
 	__maybe_unused notrace
 #endif
 
+/*
+ * gcc provides both __inline__ and __inline as alternate spellings of
+ * the inline keyword, though the latter is undocumented. New kernel
+ * code should only use the inline spelling, but some existing code
+ * uses __inline__. Since we #define inline above, to ensure
+ * __inline__ has the same semantics, we need this #define.
+ *
+ * However, the spelling __inline is strictly reserved for referring
+ * to the bare keyword.
+ */
 #define __inline__ inline
-#define __inline   inline
 
 /*
  * Rather then using noinline to prevent stack consumption, use
-- 
2.20.1