On Thu, 2021-08-26 at 13:40 -0300, Marcos Paulo de Souza wrote:

There is a common pattern when search for a key in btrfs:

 * Call btrfs_search_slot
 * Endless loop
     * If the found slot is bigger than the current items in the
leaf, check the
       next one
     * If still not found in the next leaf, return 1
     * Do something with the code
     * Increment current slot, and continue

This pattern can be improved by creating an iterator macro, similar
to
those for_each_X already existing in the linux kernel. using this
approach means to reduce significantly boilerplate code, along making
it
easier to newcomers to understand how to code works.

This patchset survived a complete fstest run.

My bad, I only added v2 to the cover-letter, but the only change from
v1 is that now the xattr changes are in a separate patch.

Changes from v1:
 * Separate xattr changes from the macro introducing code (Johannes)

Changes from RFC:
 * Add documentation to btrfs_for_each_slot macro and
btrfs_valid_slot function
   (David)
 * Add documentation about the ret variable used as a macro argument
(David)
 * Match function argument from prototype and implementation (David)
 * Changed ({ }) block to only () in btrfs_for_each_slot macro
(David)
 * Add more patches to show the code being reduced by using this
approach
   (Nikolay)

Marcos Paulo de Souza (8):
  fs: btrfs: Introduce btrfs_for_each_slot
  btrfs: block-group: use btrfs_for_each_slot in
find_first_block_group
  btrfs: dev-replace: Use btrfs_for_each_slot in
    mark_block_group_to_copy
  btrfs: dir-item: use btrfs_for_each_slot in
    btrfs_search_dir_index_item
  btrfs: inode: use btrfs_for_each_slot in btrfs_read_readdir
  btrfs: send: Use btrfs_for_each_slot macro
  btrfs: volumes: use btrfs_for_each_slot in btrfs_read_chunk_tree
  btrfs: xattr: Use btrfs_for_each_slot macro in btrfs_listxattr

 fs/btrfs/block-group.c |  33 +-----
 fs/btrfs/ctree.c       |  28 ++++++
 fs/btrfs/ctree.h       |  25 +++++
 fs/btrfs/dev-replace.c |  51 ++--------
 fs/btrfs/dir-item.c    |  27 +----
 fs/btrfs/inode.c       |  46 ++++-----
 fs/btrfs/send.c        | 222 +++++++++++--------------------------
----
 fs/btrfs/volumes.c     |  23 ++---
 fs/btrfs/xattr.c       |  40 +++-----
 9 files changed, 169 insertions(+), 326 deletions(-)