As Segher pointed out, inline asm is better than the volatile casting all over the place. From the PowerPC patch description: Also use inline functions instead of macros; this actually improves code generation (some code becomes a little smaller, probably because of improved alias information -- just a few hundred bytes total on a default kernel build, nothing shocking). My config with march=pentium-m and gcc (GCC) 4.1.2 (Gentoo 4.1.2): text data bss dec hex filename 3434150 249176 176128 3859454 3ae3fe atomic_normal/vmlinux 3435308 249176 176128 3860612 3ae884 atomic_inlineasm/vmlinux 3436201 249176 176128 3861505 3aec01 atomic_inline_volatile/vmlinux 3436203 249176 176128 3861507 3aec03 atomic_volatile/vmlinux Signed-off-by: Sebastian Siewior Cc: Andi Kleen Cc: Chris Snook --- a/include/asm-i386/atomic.h +++ b/include/asm-i386/atomic.h @@ -25,7 +25,16 @@ typedef struct { int counter; } atomic_t * * Atomically reads the value of @v. */ -#define atomic_read(v) ((v)->counter) +static inline int atomic_read(const atomic_t *v) +{ + int t; + + asm volatile( + "movl %1,%0" + : "=r"(t) + : "m"(v->counter)); + return t; +} /** * atomic_set - set atomic variable @@ -34,7 +43,13 @@ typedef struct { int counter; } atomic_t * * 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) +{ + asm volatile( + "movl %1,%0" + : "=m"(v->counter) + : "ir"(i)); +} /** * atomic_add - add integer to atomic variable -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/