On Thu 19-07-18 18:21:23, Ming Lei wrote: > On Thu, Jul 19, 2018 at 11:39:18AM +0200, Martin Wilck wrote: > > bio_iov_iter_get_pages() returns only pages for a single non-empty > > segment of the input iov_iter's iovec. This may be much less than the number > > of pages __blkdev_direct_IO_simple() is supposed to process. Call > > In bio_iov_iter_get_pages(), iov_iter_get_pages() supposes to retrieve > as many as possible pages since both 'maxsize' and 'maxpages' are provided > to cover all. > > So the question is why iov_iter_get_pages() doesn't work as expected? Well, there has never been a promise that it will grab *all* pages in the iter AFAIK. Practically, I think that it was just too hairy to implement in the macro magic that iter processing is... Al might know more (added to CC). Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
