> > > +/* Wrapper to read one metadata field to u8/u16/u32/u64 */ > > > +#define stbuf_read_sysmd_single(_field_id, _pdata) \ > > > + stbuf_read_sysmd_field(_field_id, _pdata, 0, sizeof(typeof(*(_pdata)))) > > > > What value does adding yet another level of indirection bring here? > > We could use the raw version instead: read_sys_metadata_field(). > > This wrapper additionally checks the 'element size' encoded in the field > ID matches the size that passed in, so it can catch potential kernel bug. > > But I can remove this to simplify the code. > Sorry I didn't finish my reply properly as I was interrupted. Another advantage of this wrapper is, as mentioned in the comment of it, it works with 'u8/u16/u32/u64' directly, while the raw read_sys_metadata_field() always puts data to a 'u64'. An example is, ... > > > + > > > + ret = stbuf_read_sysmd_single(MD_FIELD_ID_NUM_CMRS, > > > + &cmr_info->num_cmrs); > > > + if (ret) > > > + return ret; > > > + > > > ... here to read cmr_info->num_cmrs, which is a 'u16'. So it is helpful to me.
