Re: memcpy_toio on i386 using byte writes even when n%2==0

[H. Peter Anvin]

Followup to:  <44779358.9010703@xxxxxxx>
By author:    Robert Hancock <hancockr@xxxxxxx>
In newsgroup: linux.dev.kernel
> 
> It does seem a little bit less efficient, but I don't know think it's 
> necessarily a bug. There's no guarantee of what size writes will be used 
> with the memcpy_to/fromio functions.
> 

There are only a few semantics that make sense: fixed 8, 16, 32, or 64
bits, plus "optimal"; the latter to be used for anything that doesn't
require a specific transfer size.  Logically, an unqualified
"memcpy_to/fromio" should be the optimal size (as few transfers as
possible) -- we have a qualified "memcpy_to/fromio32" already, and 8-
and 16-bit variants could/should be added.

However, having the unqualified version do byte transfers seems like a
really bad idea.

	-hpa

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