On Mon, Dec 06, 2021 at 03:54:22PM +0100, Christoph Hellwig wrote: > On Mon, Dec 06, 2021 at 02:17:24PM +0000, Matthew Wilcox wrote: > > On Mon, Dec 06, 2021 at 03:04:51PM +0100, Christoph Hellwig wrote: > > > This looks like a huge mess. What speak against using an iov_iter > > > here? > > > > I coincidentally made a start on this last night. Happy to stop. > > Don't stop! > > > What do you think to adding a generic copy_pfn_to_iter()? Not sure > > which APIs to use to implement it ... some architectures have weird > > requirements about which APIs can be used for what kinds of PFNs. > > Hmm. I though kmap_local_pfn(_prot) is all we need? In the !HIGHMEM case, that calls pfn_to_page(), and I think the point of this path is that we don't have a struct page for this pfn.
