On Sat, Aug 29, 2020 at 01:08:51AM -0700, John Hubbard wrote: > pin_user_page() is the FOLL_PIN equivalent of get_page(). > > This was always a missing piece of the pin/unpin API calls (early > reviewers of pin_user_pages() asked about it, in fact), but until now, > it just wasn't needed. Finally though, now that the Direct IO pieces in > block/bio are about to be converted to use FOLL_PIN, it turns out that > there are some cases in which get_page() and get_user_pages_fast() were > both used. Converting those sites requires a drop-in replacement for > get_page(), which this patch supplies. I find the name really confusing vs pin_user_pages*, as it suggests as single version of the same. It also seems partially wrong, at least in the direct I/O case as the only thing pinned here is the zero page. So maybe pin_kernel_page is a better name together with an explanation? Or just pin_page?
