Pull iov_iter updates from Al Viro:
 "Cleanups that sat in -next + -stable fodder that has just missed 4.11.

  There's more iov_iter work in my local tree, but I'd prefer to push
  the stuff that had been in -next first"

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  iov_iter: don't revert iov buffer if csum error
  generic_file_read_iter(): make use of iov_iter_revert()
  generic_file_direct_write(): make use of iov_iter_revert()
  orangefs: use iov_iter_revert()
  sctp: switch to copy_from_iter_full()
  net/9p: switch to copy_from_iter_full()
  switch memcpy_from_msg() to copy_from_iter_full()
  rds: make use of iov_iter_revert()