On Fri, Sep 24, 2021 at 09:09:58PM +0800, Shiyang Ruan wrote: > +void fs_dax_register_holder(struct dax_device *dax_dev, void *holder, > + const struct dax_holder_operations *ops) > +{ > + dax_set_holder(dax_dev, holder, ops); > +} > +EXPORT_SYMBOL_GPL(fs_dax_register_holder); > + > +void fs_dax_unregister_holder(struct dax_device *dax_dev) > +{ > + dax_set_holder(dax_dev, NULL, NULL); > +} > +EXPORT_SYMBOL_GPL(fs_dax_unregister_holder); > + > +void *fs_dax_get_holder(struct dax_device *dax_dev) > +{ > + return dax_get_holder(dax_dev); > +} > +EXPORT_SYMBOL_GPL(fs_dax_get_holder); These should not be in a XFS patch. But why do we even need this wrappers? > @@ -377,6 +385,8 @@ xfs_close_devices( > > xfs_free_buftarg(mp->m_logdev_targp); > xfs_blkdev_put(logdev); > + if (dax_logdev) > + fs_dax_unregister_holder(dax_logdev); > fs_put_dax(dax_logdev); I'd prefer to include the fs_dax_unregister_holder in the fs_put_dax call to avoid callers failing to unregister it. > @@ -411,6 +425,9 @@ xfs_open_devices( > struct block_device *logdev = NULL, *rtdev = NULL; > int error; > > + if (dax_ddev) > + fs_dax_register_holder(dax_ddev, mp, > + &xfs_dax_holder_operations); I'd include the holder registration with fs_dax_get_by_bdev as well.