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

From: Andreas Schwab
Date: Wed Mar 30 2011 - 09:51:42 EST


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.

Andreas.

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