Re: [PATCH] blk-throttle: don't call xchg on bool

From: Vivek Goyal
Date: Wed Mar 30 2011 - 12:53:52 EST


On Wed, Mar 30, 2011 at 03:51:34PM +0200, Andreas Schwab wrote:
> Vivek Goyal <vgoyal@xxxxxxxxxx> writes:
>
> > Which arch creates the problem and what's the issue here if data type
> > is smaller than 32bit?
>
> Just look at the various implementations in arch/*/include/asm/system.h:
>
> - arm: supports only one and 4 byte xchg
> - avr32: supports only 4 byte xchg
> - frv: supports only 4 byte xchg
> - m32r: SMP supports only 4 byte xchg
> - microblaze: supports only one and 4 byte xchg
>
> etc.
>
> > Is it a compile time warning?
>
> Most implementations turn the use of xchg with a bad pointer into a link
> error.

Thanks Andreas. I get it. I did check arm and it is supporting only one
and 4 byte xchg.

Vivek
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