Re: [mingo@elte.hu: [git pull] headers_check fixes]

From: Linus Torvalds
Date: Wed Jan 28 2009 - 14:44:57 EST




On Wed, 28 Jan 2009, Harvey Harrison wrote:
> On Wed, 2009-01-28 at 09:48 -0800, H. Peter Anvin wrote:
> >
> > In general, no. The byteswap API is a legacy exception.
>
> But now that swab.h has been separated out, we could just stop exporting the
> asm/swab.h bits while still providing a generic C-based implementation to
> userspace.

Well, the _reason_ the byteswap stuff has been interesting to user space
is that the kernel did it better than the alternatives. Rather than having
purely "work with big-endian data" (the networking htonl etc functions),
the kernel had good and fairly optimized handling of various different
forms of byte order handling.

Which is why people wanted to use it in the first place - and which is why
then doing just the generic C-based thing doesn't really fix the issue.
Things may compile, but they kind of lost the point.

Linus
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