Re: [PATCH] x86: remove unused atomic_inc_short()

From: Andrey Ryabinin
Date: Wed Mar 22 2017 - 12:12:28 EST




On 03/22/2017 05:10 PM, Dmitry Vyukov wrote:
> It is completely unused and implemented only on x86.
> Remove it.
>
> Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Suggested-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>

Not me, it was Mark Rutland <mark.rutland@xxxxxxx>

> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: x86@xxxxxxxxxx
>
> ---
>
> Andrew, I think it needs to go into mm as
> the atomic-instrumented.h patch is in mm.
> ---
> arch/tile/lib/atomic_asm_32.S | 3 +--
> arch/x86/include/asm/atomic.h | 13 -------------
> include/asm-generic/atomic-instrumented.h | 6 ------
> 3 files changed, 1 insertion(+), 21 deletions(-)
>
> diff --git a/arch/tile/lib/atomic_asm_32.S b/arch/tile/lib/atomic_asm_32.S
> index 1a70e6c0f259..94709ab41ed8 100644
> --- a/arch/tile/lib/atomic_asm_32.S
> +++ b/arch/tile/lib/atomic_asm_32.S
> @@ -24,8 +24,7 @@
> * has an opportunity to return -EFAULT to the user if needed.
> * The 64-bit routines just return a "long long" with the value,
> * since they are only used from kernel space and don't expect to fault.
> - * Support for 16-bit ops is included in the framework but we don't provide
> - * any (x86_64 has an atomic_inc_short(), so we might want to some day).
> + * Support for 16-bit ops is included in the framework but we don't provide any.
> *
> * Note that the caller is advised to issue a suitable L1 or L2
> * prefetch on the address being manipulated to avoid extra stalls.
> diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
> index 0cde164f058a..9ff8738103eb 100644
> --- a/arch/x86/include/asm/atomic.h
> +++ b/arch/x86/include/asm/atomic.h
> @@ -237,19 +237,6 @@ ATOMIC_OPS(xor, ^)
>
> int __arch_atomic_add_unless(atomic_t *v, int a, int u);
>
> -/**
> - * arch_atomic_inc_short - increment of a short integer
> - * @v: pointer to type int
> - *
> - * Atomically adds 1 to @v
> - * Returns the new value of @u
> - */
> -static __always_inline short int arch_atomic_inc_short(short int *v)
> -{
> - asm(LOCK_PREFIX "addw $1, %0" : "+m" (*v));
> - return *v;
> -}
> -
> #ifdef CONFIG_X86_32
> # include <asm/atomic64_32.h>
> #else
> diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h
> index 951bcd083925..70742da13087 100644
> --- a/include/asm-generic/atomic-instrumented.h
> +++ b/include/asm-generic/atomic-instrumented.h
> @@ -78,12 +78,6 @@ static __always_inline bool atomic64_add_unless(atomic64_t *v, long long a,
> return arch_atomic64_add_unless(v, a, u);
> }
>
> -static __always_inline short int atomic_inc_short(short int *v)
> -{
> - kasan_check_write(v, sizeof(*v));
> - return arch_atomic_inc_short(v);
> -}
> -
> #define __INSTR_VOID1(op, sz) \
> static __always_inline void atomic##sz##_##op(atomic##sz##_t *v) \
> { \
>