On Mon, Sep 10, 2018 at 04:43:29PM -0700, Omar Sandoval wrote:
> On Mon, Sep 10, 2018 at 07:22:31PM +0200, David Sterba wrote:
> > Avoid the inline ifdefs and use two sections for self-tests enabled and
> > disabled.
> >
> > Signed-off-by: David Sterba <dsterba@xxxxxxxx>
> > ---
> > fs/btrfs/ctree.h | 9 ++++++---
> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> > index 32d2fce4ac53..8dafc7bb6ad8 100644
> > --- a/fs/btrfs/ctree.h
> > +++ b/fs/btrfs/ctree.h
> > @@ -3708,17 +3708,20 @@ static inline int btrfs_defrag_cancelled(struct btrfs_fs_info *fs_info)
> > #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
> > void btrfs_test_inode_set_ops(struct inode *inode);
> > void btrfs_test_destroy_inode(struct inode *inode);
> > -#endif
> >
> > static inline int btrfs_is_testing(struct btrfs_fs_info *fs_info)
> > {
> > -#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
> > if (unlikely(test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO,
> > &fs_info->fs_state)))
> > return 1;
> > -#endif
> > return 0;
>
> How about just:
>
> return test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state);
>
> We can probably get away without the unlikely() considering that no one
> sane is going to run a kernel with CONFIG_BTRFS_FS_RUN_SANITY_TESTS in
> production.
The unlikely can go away, sure.
I would still like to remove the test_bit call when tests are compiled
out. There are about 10 calls to btrfs_is_testing in various core
functions, followed by further statements. This would have a
(negligible) runtime penalty but generates effectively unused code on
production builds.
The static inline function returning 0 allows to optimize out the unused
code, so smaller code, fewer inctructions, etc.
