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SubjectRe: memcpy_toio on i386 using byte writes even when n%2==0
Date
Followup to:  <44779358.9010703@shaw.ca>
By author: Robert Hancock <hancockr@shaw.ca>
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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