Pull iov_iter updates from Al Viro:

 - bio_{map,copy}_user_iov() series; those are cleanups - fixes from the
   same pile went into mainline (and stable) in late September.

 - fs/iomap.c iov_iter-related fixes

 - new primitive - iov_iter_for_each_range(), which applies a function
   to kernel-mapped segments of an iov_iter.

   Usable for kvec and bvec ones, the latter does kmap()/kunmap() around
   the callback. _Not_ usable for iovec- or pipe-backed iov_iter; the
   latter is not hard to fix if the need ever appears, the former is by
   design.

   Another related primitive will have to wait for the next cycle - it
   passes page + offset + size instead of pointer + size, and that one
   will be usable for everything _except_ kvec. Unfortunately, that one
   didn't get exposure in -next yet, so...

 - a bit more lustre iov_iter work, including a use case for
   iov_iter_for_each_range() (checksum calculation)

 - vhost/scsi leak fix in failure exit

 - misc cleanups and detritectomy...

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (21 commits)
  iomap_dio_actor(): fix iov_iter bugs
  switch ksocknal_lib_recv_...() to use of iov_iter_for_each_range()
  lustre: switch struct ksock_conn to iov_iter
  vhost/scsi: switch to iov_iter_get_pages()
  fix a page leak in vhost_scsi_iov_to_sgl() error recovery
  new primitive: iov_iter_for_each_range()
  lnet_return_rx_credits_locked: don't abuse list_entry
  xen: don't open-code iov_iter_kvec()
  orangefs: remove detritus from struct orangefs_kiocb_s
  kill iov_shorten()
  bio_alloc_map_data(): do bmd->iter setup right there
  bio_copy_user_iov(): saner bio size calculation
  bio_map_user_iov(): get rid of copying iov_iter
  bio_copy_from_iter(): get rid of copying iov_iter
  move more stuff down into bio_copy_user_iov()
  blk_rq_map_user_iov(): move iov_iter_advance() down
  bio_map_user_iov(): get rid of the iov_for_each()
  bio_map_user_iov(): move alignment check into the main loop
  don't rely upon subsequent bio_add_pc_page() calls failing
  ... and with iov_iter_get_pages_alloc() it becomes even simpler
  ...