[PATCH 0/7] btrfs: Create macro to iterate slots

Marcos Paulo de Souza
2021-08-24T17:09:59Z

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.

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 (7):
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

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(-)

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2.31.1