[Cluster-devel] [PATCH v7 05/19] iov_iter: Introduce fault_in_iov_iter_writeable
viro at zeniv.linux.org.uk
Fri Aug 27 19:23:49 UTC 2021
On Fri, Aug 27, 2021 at 12:05:32PM -0700, Linus Torvalds wrote:
> But see above. People *need* that ternary result, and "bytes/pages
> uncopied" is not only the traditional one we use elsewhere in similar
> situations, it's the one that has the easiest error tests for existing
> users (because zero remains "everything worked").
Could you show the cases where "partial copy, so it's OK" behaviour would
For that you would need the case where
partial fault-in is currently rejected by the check
checks downstream from there (for failing copy-in/copy-out) would
be either missing or would not be handled correctly in case of partial
fault-in or would slow a fast path down.
I don't see any such cases and I would be very surprised if such existed.
If you see any, please describe them - I could be wrong. And I would
like to take a good look at any such case and see how well does it handle
possible short copy after full fault-in.
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