Re: [PATCH] userfaultfd: hugetlbfs: add UFFDIO_COPY support for shared mappings

From: Andrea Arcangeli
Date: Fri Feb 17 2017 - 15:51:32 EST

On Fri, Feb 17, 2017 at 12:17:38PM -0800, Andrew Morton wrote:
> I merged this up and a small issue remains:


> The value of `err' here is EINVAL. That sems appropriate, but it only
> happens by sheer luck.

It might have been programmer luck but just for completeness, at
runtime no luck was needed (the temporary setting to ENOENT is undoed
before the if clause is closed). Your addition is surely safer just in
case of future changes missing how we inherited the EINVAL in both
branches, thanks! (plus the compiler should be able to optimize it
away until after it will be needed)