Re: [PATCH 0/5] spapr: Error handling fixes and cleanups (round 3)

[Greg Kurz]

On Thu, 22 Oct 2020 15:11:42 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Mon, Oct 19, 2020 at 10:47:52AM +0200, Greg Kurz wrote:
> > Hi,
> > 
> > This is a followup to a previous cleanup for the sPAPR code:
> > 
> > https://lists.gnu.org/archive/html/qemu-devel/2020-09/msg04860.html
> > 
> > The last two patches had to be dropped because they were wrongly assuming
> > that object_property_get_uint() returning zero meant failure. This led to
> > a discussion in which arose a consensus that most of the time (not to say
> > always) object property getters should never fail actually, ie. failure
> > is very likely the result of a programming error and QEMU should abort.
> > 
> > This series aims at demonstrating a revelant case I've found while auditing
> > object property getters (this is patch 4 that I've isolated from a huge
> > 50-patch series I haven't dared to post yet). The sPAPR memory hotplug code
> > is tailored to support either regular PC DIMMs or NVDIMMs, which inherit
> > from PC DIMMs. They expect to get some properties from the DIMM object,
> > which happens to be set by default at the PC DIMM class level. It thus
> > doesn't make sense to pass an error object and propagate it when getting
> > them since this would lure the user into thinking they did something wrong.
> > 
> > Some preliminary cleanup is done on the way, especially dropping an unused
> > @errp argument of pc_dimm_plug(). This affects several platforms other than
> > sPAPR but I guess the patch is trivial enough to go through David's tree
> > if it gets acks from the relevant maintainers.
> 
> Since this series mostly affects ppc, I've applied it to ppc-for-5.2.
> 
> It would be nice to have an acked-by from Igor or Michael for the
> first patch, though.
> 

David,

Igor sent a R-b for patches 1 and 4. He also suggested to call
spapr_drc_attach() at pre-plug time. I'll look into this, so maybe
you can drop patch 5 from ppc-for-5.2 (or the entire series at
your convenience).

Cheers,

--
Greg

> > 
> > ---
> > 
> > Greg Kurz (5):
> >       pc-dimm: Drop @errp argument of pc_dimm_plug()
> >       spapr: Use appropriate getter for PC_DIMM_ADDR_PROP
> >       spapr: Use appropriate getter for PC_DIMM_SLOT_PROP
> >       spapr: Pass &error_abort when getting some PC DIMM properties
> >       spapr: Simplify error handling in spapr_memory_plug()
> > 
> > 
> >  hw/arm/virt.c                 |    9 +-------
> >  hw/i386/pc.c                  |    8 +------
> >  hw/mem/pc-dimm.c              |    2 +-
> >  hw/ppc/spapr.c                |   48 
> > +++++++++++++++--------------------------
> >  hw/ppc/spapr_nvdimm.c         |    5 +++-
> >  include/hw/mem/pc-dimm.h      |    2 +-
> >  include/hw/ppc/spapr_nvdimm.h |    2 +-
> >  7 files changed, 25 insertions(+), 51 deletions(-)
> > 
>

pgpZ5zk7iPxRf.pgp
Description: OpenPGP digital signature