btrfs: remove op field from struct btrfs_free_space_ctl

The op field always points to the same use_bitmap function, the only
exception is during self tests where we make it temporarily point to a
different function. So just because of this op pointer field we are
increasing the structure size by 8 bytes.

Instead of storing a pointer to a use_bitmap function in struct
btrfs_free_space_ctl, move the pointer to struct btrfs_info, make
insert_into_bitmap() use that pointer if we are running the self tests
and initialize that pointer to the current, default use_bitmap function
(now exported for the tests as btrfs_use_bitmap). This way we reduce
the size of struct btrfs_free_space_ctl from 136 to 128 bytes and can
now fit 32 structures in a 4K page instead of 30. This also avoids the
cost of the indirection of a function pointer call when we are not
running the self tests.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

0 files changed, 0 insertions, 0 deletions