Re: NFS structure allocation alignment patch

From: David Woodhouse (dwmw2@infradead.org)
Date: Fri Jul 18 2003 - 11:10:39 EST


On Wed, 2003-07-16 at 16:03, Richard Curnow wrote:
> Apart from this issue, we haven't seen any code- or compiler-related
> problems due to misaligned loads and stores occurring.

That doesn't mean they don't exist. Various parts of the network code
_require_ alignment fixups -- the common case is that it'll be aligned,
and we take the hit only in the _rare_ case of misalignment rather than
using get_unaligned() in the fast path.

Also the flash code does the same in places too. It _did_ use
get_unaligned() for a while but it was removed since it's never valid
for an architecture to _not_ fix up unaligned in-kernel accesses.

> I bet someone will wonder how the misalignment hadn't shown up before.

Because all other architectures implement alignment fixups.

-- 
dwmw2

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