x86: atomic64: Code atomic(64)_read and atomic(64)_set in C not CPP

Occasionally we get bugs where atomic_read or atomic_set are
used on atomic64_t variables or vice versa.  These bugs don't
generate warnings on x86 because atomic_read and atomic_set are
coded as macros rather than C functions, so we don't get any
type-checking on their arguments; similarly for atomic64_read
and atomic64_set in 64-bit kernels.

This converts them to C functions so that the arguments are
type-checked and bugs like this will get caught more easily. It
also converts atomic_cmpxchg and atomic_xchg, and
atomic64_cmpxchg and atomic64_xchg on 64-bit, so we get
type-checking on their arguments too.

Compiling a typical 64-bit x86 config, this generates no new
warnings, and the vmlinux text is 86 bytes smaller.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 13 insertions, 3 deletions

diff --git a/arch/x86/include/asm/atomic_32.h b/arch/x86/include/asm/atomic_32.h
index b551bb1ae3cf..aa045deb2e75 100644
--- a/arch/x86/include/asm/atomic_32.h
+++ b/arch/x86/include/asm/atomic_32.h
@@ -31,7 +31,10 @@ static inline int atomic_read(const atomic_t *v)
  *
  * Atomically sets the value of @v to @i.
  */
-#define atomic_set(v, i)        (((v)->counter) = (i))
+static inline void atomic_set(atomic_t *v, int i)
+{
+        v->counter = i;
+}
 
 /**
  * atomic_add - add integer to atomic variable
@@ -203,8 +206,15 @@ static inline int atomic_sub_return(int i, atomic_t *v)
         return atomic_add_return(-i, v);
 }
 
-#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
-#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
+static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
+{
+        return cmpxchg(&v->counter, old, new);
+}
+
+static inline int atomic_xchg(atomic_t *v, int new)
+{
+        return xchg(&v->counter, new);
+}
 
 /**
  * atomic_add_unless - add unless the number is already a given value