Hi, thanks for reviewing. On Fri, Jul 28, 2023 at 03:26:57PM -0700, Kees Cook wrote: > Doing build comparisons here, I see a lot of binary changes. They may > be, as you say, harmless, and since you've actually got hardware then > this is a good verification of the changes, but I do wonder if this > needs more detailed commit log (or split up patches). > > However, the problem I see is that this code was already doing weird > stuff with structs that appear to not have been using flex arrays > actually. With "pahole" I can see struct MPT3SAS_ADAPTER changes: > > - Mpi2IOUnitPage8_t iounit_pg8; /* 3668 40 */ > - Mpi2IOCPage1_t ioc_pg1_copy; /* 3708 24 */ > + Mpi2IOUnitPage8_t iounit_pg8; /* 3668 16 */ > + Mpi2IOCPage1_t ioc_pg1_copy; /* 3684 24 */ > > struct _MPI2_CONFIG_PAGE_IO_UNIT_8 (Mpi2IOUnitPage8_t) is in the > _middle_ of struct MPT3SAS_ADAPTER.... :| In this particular case, the flex array member of iounit_pg8 is never used, and iounit_pg8 itself is never used outside of the function that fetches and sets it on the per-adapter struct MPT3SAS_ADAPTER. iounit_pg8 could probably be removed, now that I think about it. Maybe I will. > In the earlier attempts at this conversion, it seemed that some of these > are actually fixed-size: > > https://lore.kernel.org/lkml/20210202235118.GA314410@embeddedor/ Yes, I tried to leave such terminal arrays alone. But I'll revisit each change in this commit. > I think this patch needs to be broken up into per-struct changes, so > they can be reviewed individually. Sure, I can do that. I'll resubmit this commit and the one following (which depends on this commit) as a new series with more details. Hopefully this will encourage the Broadcom folks who know this driver best to chime in as well. By the way, I noticed you've done something like this in the past to preserve struct size for userspace, just in case: /* MPI2_IOUNIT8_SENSOR Sensor[1]; */ union { MPI2_IOUNIT8_SENSOR _LegacyPadding; __DECLARE_FLEX_ARRAY(MPI2_IOUNIT8_SENSOR, Sensor); }; I don't think userspace is a concern for us here, but would you be more comfortable if I did this too/instead? James
