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Subject[PATCH -tip] x86: atomic64: inline atomic64_read()
Now atomic64_read() is light weight (no register pressure and
small icache), we can inline it again.

Also use "=&A" constraint instead of "+A" to avoid warning
about unitialized 'res' variable. (gcc had to force 0 in eax/edx)


$ size vmlinux.prev vmlinux.after
text data bss dec hex filename
4908667 451676 1684868 7045211 6b805b vmlinux.prev
4908651 451676 1684868 7045195 6b804b vmlinux.after

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---
arch/x86/include/asm/atomic_32.h | 15 +++++++++++++++
arch/x86/lib/atomic64_32.c | 21 ---------------------
2 files changed, 15 insertions(+), 21 deletions(-)
diff --git a/arch/x86/include/asm/atomic_32.h b/arch/x86/include/asm/atomic_32.h
index aa045de..0332041 100644
--- a/arch/x86/include/asm/atomic_32.h
+++ b/arch/x86/include/asm/atomic_32.h
@@ -304,6 +304,21 @@ extern void atomic64_set(atomic64_t *ptr, u64 new_val);
*
* Atomically reads the value of @ptr and returns it.
*/
+static inline u64 atomic64_read(atomic64_t *ptr)
+{
+ u64 res;
+
+ asm volatile(
+ "mov %%ebx, %%eax\n\t"
+ "mov %%ecx, %%edx\n\t"
+ LOCK_PREFIX "cmpxchg8b %1\n"
+ : "=&A" (res)
+ : "m" (*ptr)
+ );
+
+ return res;
+}
+
extern u64 atomic64_read(atomic64_t *ptr);

/**
diff --git a/arch/x86/lib/atomic64_32.c b/arch/x86/lib/atomic64_32.c
index cd11803..cb51226 100644
--- a/arch/x86/lib/atomic64_32.c
+++ b/arch/x86/lib/atomic64_32.c
@@ -55,27 +55,6 @@ void atomic64_set(atomic64_t *ptr, u64 new_val)
}

/**
- * atomic64_read - read atomic64 variable
- * @ptr: pointer to type atomic64_t
- *
- * Atomically reads the value of @ptr and returns it.
- */
-u64 atomic64_read(atomic64_t *ptr)
-{
- u64 res;
-
- asm volatile(
- "mov %%ebx, %%eax\n\t"
- "mov %%ecx, %%edx\n\t"
- LOCK_PREFIX "cmpxchg8b %1\n"
- : "+A" (res)
- : "m" (*ptr)
- );
-
- return res;
-}
-
-/**
* atomic64_add_return - add and return
* @delta: integer value to add
* @ptr: pointer to type atomic64_t

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