On Thu, Oct 22, 2020 at 04:04:16PM -0700, James Bottomley wrote:
> On Thu, 2020-10-22 at 15:06 -0700, Moritz Fischer wrote:
> > The driver does not implement a shutdown handler which leads to
> > issues
> > when using kexec in certain scenarios. The NIC keeps on fetching
> > descriptors which gets flagged by the IOMMU with errors like this:
> >
> > DMAR: DMAR:[DMA read] Request device [5e:00.0]fault addr fffff000
> > DMAR: DMAR:[DMA read] Request device [5e:00.0]fault addr fffff000
> > DMAR: DMAR:[DMA read] Request device [5e:00.0]fault addr fffff000
> > DMAR: DMAR:[DMA read] Request device [5e:00.0]fault addr fffff000
> > DMAR: DMAR:[DMA read] Request device [5e:00.0]fault addr fffff000
> >
> > Signed-off-by: Moritz Fischer <mdf@xxxxxxxxxx>
> > ---
> >
> > Hi all,
> >
> > I'm not sure if this is the proper way for a shutdown handler,
> > I've tried to look at a bunch of examples and couldn't find a
> > specific
> > solution, in my tests on hardware this works, though.
> >
> > Open to suggestions.
> >
> > Thanks,
> > Moritz
> >
> > ---
> > drivers/net/ethernet/dec/tulip/de2104x.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/net/ethernet/dec/tulip/de2104x.c
> > b/drivers/net/ethernet/dec/tulip/de2104x.c
> > index f1a2da15dd0a..372c62c7e60f 100644
> > --- a/drivers/net/ethernet/dec/tulip/de2104x.c
> > +++ b/drivers/net/ethernet/dec/tulip/de2104x.c
> > @@ -2185,6 +2185,7 @@ static struct pci_driver de_driver = {
> > .id_table = de_pci_tbl,
> > .probe = de_init_one,
> > .remove = de_remove_one,
> > + .shutdown = de_remove_one,
>
> This doesn't look right: shutdown is supposed to turn off the device
> without disturbing the tree or causing any knock on effects (I think
> that rule is mostly because you don't want anything in userspace
> triggering since it's likely to be nearly dead). Remove removes the
> device from the tree and cleans up everything. I think the function
> you want that's closest to what shutdown needs is de_close(). That
> basically just turns off the chip and frees the interrupt ... you'll
> have to wrapper it to call it from the pci_driver, though.
Thanks for the suggestion, I like that better. I'll send a v2 after
testing.
I think anything that hits on de_stop_hw() will keep the NIC from
fetching further descriptors.
Cheers,
Moritz
