On Wed, Jan 19, 2022 at 7:37 PM Anshuman Khandual <anshuman.khandual@xxxxxxx> wrote: > > > > On 1/19/22 10:52 PM, Yury Norov wrote: > >> Why should not this just scan over the entire user provided struct page > >> array and make sure that all pages there in are valid via above method, > >> but in vmap() itself before calling vmap_pages_range(). Because seems > >> like a single invalid page detected in vmap_pages_pte_range() will > >> anyways abort the entire vmap(). This will also enable us to drop the > >> existing NULL check above. > > > > I can do this, but why is it any better than the current approach? > > Because it will just return on the first instance where the valid page > check fails, saving us some CPU cycles and an incomplete mapping ? This should normally never happen, that's why warn_on() is there. If it happens, there is a serious problem, and the code must be fixed. So, no CPU cycles saving in real life.
