Re: [PATCH] Document Linux's memory barriers

Nick Piggin
2006-03-08T07:41:35Z

Paul Mackerras wrote:
> David Howells writes:

>>+ The way to deal with this is to insert an I/O memory barrier between the
>>+ two accesses:
>>+
>>+ *ADR = ctl_reg_3;
>>+ mb();
>>+ reg = *DATA;
>
>
> Ummm, this implies mb() is "an I/O memory barrier". I can see people
> getting confused if they read this and then see mb() being used when
> no I/O is being done.
>

Isn't it? Why wouldn't you just use smp_mb() if no IO is being done?

--
SUSE Labs, Novell Inc.
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