On Sat, Sep 23, 2017 at 06:19:26PM +0100, Al Viro wrote: > On Sat, Sep 23, 2017 at 05:55:37PM +0100, Al Viro wrote: > > > IOW, the loop on failure exit should go through the bio, like __bio_unmap_user() > > does. We *also* need to put everything left unused in pages[], but only from the > > last iteration through iov_for_each(). > > > > Frankly, I would prefer to reuse the pages[], rather than append to it on each > > iteration. Used iov_iter_get_pages_alloc(), actually. > > Something like completely untested diff below, perhaps... > + unsigned n = PAGE_SIZE - offs; > + unsigned prev_bi_vcnt = bio->bi_vcnt; Sorry, that should've been followed by if (n > bytes) n = bytes; Anyway, a carved-up variant is in vfs.git#work.iov_iter. It still needs review and testing; the patch Vitaly has posted in this thread plus 6 followups, hopefully more readable than aggregate diff. Comments?
