On Mon, Jan 25, 2021 at 08:43:25PM +0100, Roman Anasal wrote:

btrfs_compare_trees and changed_cb use a void *ctx parameter instead of
struct send_ctx *sctx but when used in changed_cb it is immediately
casted to `struct send_ctx *sctx = ctx;`.

changed_cb is only ever called from btrfs_compare_trees and full_send_tree:
- full_send_tree already passes a struct send_ctx *sctx
- btrfs_compare_trees is only called by send_subvol with a struct send_ctx *sctx
- void *ctx in btrfs_compare_trees is only used to be passed to changed_cb

So casting to/from void *ctx seems unnecessary and directly using
struct send_ctx *sctx instead provides better type-safety.

The original reason for using void *ctx in the first place seems to have
been dropped with
1b51d6f ("btrfs: send: remove indirect callback parameter for changed_cb")

Signed-off-by: Roman Anasal <redacted>

Makes sense, added to misc-next, thanks.