linux-kernel - Re: [PATCH] x86: simplify sync_test

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Message-ID: <47DA93D0.4050708@goop.org>
Date:	Fri, 14 Mar 2008 08:03:44 -0700
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Jan Beulich <jbeulich@...ell.com>
CC:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: simplify sync_test_bit()

Jan Beulich wrote:
> There really is no need for a redundant implementation here, just keep
> the alternative name for allowing consumers to use consistent naming.
>
> Signed-off-by: Jan Beulich <jbeulich@...ell.com>
>
> --- a/include/asm-x86/sync_bitops.h
> +++ b/include/asm-x86/sync_bitops.h
> @@ -130,26 +130,7 @@ static inline int sync_test_and_change_b
>  	return oldbit;
>  }
>  
> -static __always_inline int sync_constant_test_bit(int nr, const volatile unsigned long *addr)
> -{
> -	return ((1UL << (nr & 31)) &
> -		(((const volatile unsigned int *)addr)[nr >> 5])) != 0;
> -}
> -
> -static inline int sync_var_test_bit(int nr, const volatile unsigned long * addr)
> -{
> -	int oldbit;
> -
> -	__asm__ __volatile__("btl %2,%1\n\tsbbl %0,%0"
> -			     :"=r" (oldbit)
> -			     :"m" (ADDR),"Ir" (nr));
> -	return oldbit;
> -}
> -
> -#define sync_test_bit(nr,addr)			\
> -	(__builtin_constant_p(nr) ?		\
> -	 sync_constant_test_bit((nr),(addr)) :	\
> -	 sync_var_test_bit((nr),(addr)))
> +#define sync_test_bit test_bit
Hm,

#define sync_test_bit(nr, addr) test_bit(nr, addr)

would be better, but seems reasonable to me. Or even an inline for 
consistency.

J
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