Pull cifs iovec cleanups from Al Viro.

* 'sendmsg.cifs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  cifs: don't bother with kmap on read_pages side
  cifs_readv_receive: use cifs_read_from_socket()
  cifs: no need to wank with copying and advancing iovec on recvmsg side either
  cifs: quit playing games with draining iovecs
  cifs: merge the hash calculation helpers