On Mon, Aug 05, 2019 at 03:54:35PM -0700, John Hubbard wrote: > On 7/23/19 11:17 PM, Christoph Hellwig wrote: > > On Tue, Jul 23, 2019 at 09:25:06PM -0700, john.hubbard@xxxxxxxxx wrote: > >> * Store, in the iov_iter, a "came from gup (get_user_pages)" parameter. > >> Then, use the new iov_iter_get_pages_use_gup() to retrieve it when > >> it is time to release the pages. That allows choosing between put_page() > >> and put_user_page*(). > >> > >> * Pass in one more piece of information to bio_release_pages: a "from_gup" > >> parameter. Similar use as above. > >> > >> * Change the block layer, and several file systems, to use > >> put_user_page*(). > > > > I think we can do this in a simple and better way. We have 5 ITER_* > > types. Of those ITER_DISCARD as the name suggests never uses pages, so > > we can skip handling it. ITER_PIPE is rejected іn the direct I/O path, > > which leaves us with three. > > > > Hi Christoph, > > Are you working on anything like this? I was hoping I could steer you towards it. But if you don't want to do it yourself I'll add it to my ever growing todo list. > Or on the put_user_bvec() idea? I have a prototype from two month ago: http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/gup-bvec but that only survived the most basic testing, so it'll need more work, which I'm not sure when I'll find time for.
