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From: Russell King <rmk@arm.linux.org.uk>
To: Luca Barbieri <ldb@ldb.ods.org>
Cc: Linux-Kernel ML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] [2.5] asm-generic/atomic.h and changes to arm, parisc, mips, m68k, sh, cris to use it
Date: Fri, 9 Aug 2002 00:29:58 +0100	[thread overview]
Message-ID: <20020809002958.B20257@flint.arm.linux.org.uk> (raw)
In-Reply-To: <1028842995.1669.70.camel@ldb>; from ldb@ldb.ods.org on Thu, Aug 08, 2002 at 11:43:15PM +0200

On Thu, Aug 08, 2002 at 11:43:15PM +0200, Luca Barbieri wrote:
>...

Please don't do this for ARM.

> -static inline int atomic_dec_and_test(volatile atomic_t *v)
> -{
> -	unsigned long flags;
> -	int val;
> -
> -	local_irq_save(flags);
> -	val = v->counter;
> -	v->counter = val -= 1;
> -	local_irq_restore(flags);
> -
> -	return val == 0;
> -}

This C code is carefully optimised to allow the compiler to order things
efficiently.

-- 
Russell King (rmk@arm.linux.org.uk)                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html


  parent reply	other threads:[~2002-08-08 23:26 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-08-08 21:43 [PATCH] [2.5] asm-generic/atomic.h and changes to arm, parisc, mips, m68k, sh, cris to use it Luca Barbieri
2002-08-08 21:58 ` Roman Zippel
2002-08-08 22:11   ` Luca Barbieri
2002-08-08 22:27     ` Roman Zippel
2002-08-08 22:40       ` Luca Barbieri
2002-08-08 23:04         ` Roman Zippel
2002-08-09  0:11         ` Alan Cox
2002-08-08 23:09           ` Luca Barbieri
2002-08-09  3:52           ` H. Peter Anvin
2002-08-08 23:45     ` Alan Cox
2002-08-12 11:16       ` David Woodhouse
2002-08-12 12:03         ` Luca Barbieri
2002-08-08 23:29 ` Russell King [this message]
2002-08-09  0:41   ` [PATCH] [2.5] (v2) " Luca Barbieri

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