Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull iov_iter updates from Al Viro:
 "iov_iter cleanups and fixes.

  There are followups, but this is what had sat in -next this cycle. IMO
  the macro forest in there became much thinner and easier to follow..."

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
  csum_and_copy_to_pipe_iter(): leave handling of csum_state to caller
  clean up copy_mc_pipe_to_iter()
  pipe_zero(): we don't need no stinkin' kmap_atomic()...
  iov_iter: clean csum_and_copy_...() primitives up a bit
  copy_page_from_iter(): don't need kmap_atomic() for kvec/bvec cases
  copy_page_to_iter(): don't bother with kmap_atomic() for bvec/kvec cases
  iterate_xarray(): only of the first iteration we might get offset != 0
  pull handling of ->iov_offset into iterate_{iovec,bvec,xarray}
  iov_iter: make iterator callbacks use base and len instead of iovec
  iov_iter: make the amount already copied available to iterator callbacks
  iov_iter: get rid of separate bvec and xarray callbacks
  iov_iter: teach iterate_{bvec,xarray}() about possible short copies
  iterate_bvec(): expand bvec.h macro forest, massage a bit
  iov_iter: unify iterate_iovec and iterate_kvec
  iov_iter: massage iterate_iovec and iterate_kvec to logics similar to iterate_bvec
  iterate_and_advance(): get rid of magic in case when n is 0
  csum_and_copy_to_iter(): massage into form closer to csum_and_copy_from_iter()
  iov_iter: replace iov_iter_copy_from_user_atomic() with iterator-advancing variant
  [xarray] iov_iter_npages(): just use DIV_ROUND_UP()
  iov_iter_npages(): don't bother with iterate_all_kinds()
  ...

1 files changed, 9 insertions, 0 deletions

diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst
index 0302035781be..43b492d08dec 100644
--- a/Documentation/filesystems/porting.rst
+++ b/Documentation/filesystems/porting.rst
@@ -890,3 +890,12 @@ been called or returned with non -EIOCBQUEUED code.
 
 mnt_want_write_file() can now only be paired with mnt_drop_write_file(),
 whereas previously it could be paired with mnt_drop_write() as well.
+
+---
+
+**mandatory**
+
+iov_iter_copy_from_user_atomic() is gone; use copy_page_from_iter_atomic().
+The difference is copy_page_from_iter_atomic() advances the iterator and
+you don't need iov_iter_advance() after it.  However, if you decide to use
+only a part of obtained data, you should do iov_iter_revert().