RE: [PATCH v4] tee: Use iov_iter to better support shared buffer registration

[David Laight]

> > As Jens Wiklander has proposed using iov_iter_ubuf() instead of
> > import_ubuf(), should I propose a patch updating import_ubuf() and
> > import_single_range()? Or would you prefer that we keep the functions
> > unchanged for the time being?
> 
> Arguably it should be consistent with iovec imports, which return the
> length (or error). But it might be safer to just check access_ok()
> first and then truncate at least, vs what is there now.

Is the access_ok() check even needed when setting up an iov_iter?
It is always checked again when the actual copy is done.

I looked at this a while back and couldn't see any code paths that
relied on the early access_ok() check.
Maybe it is historic?

	David

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