Re: [PATCH v2 3/6] powerpc/eeh: Improve debug messages around device addition

["Oliver O'Halloran" <oohall@gmail.com>]

On Thu, Jun 20, 2019 at 12:40 PM Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
>
> On 19/06/2019 14:27, Sam Bobroff wrote:
> > On Tue, Jun 11, 2019 at 03:47:58PM +1000, Alexey Kardashevskiy wrote:
> >>
> >> On 07/05/2019 14:30, Sam Bobroff wrote:
> >>> Also remove useless comment.
> >>>
> >>> Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
> >>> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> >>> ---
> *snip*
> >
> > I can see that edev will be non-NULL here, but that pr_debug() pattern
> > (using the PDN information to form the PCI address) is quite common
> > across the EEH code, so I think rather than changing a couple of
> > specific cases, I should do a separate cleanup patch and introduce
> > something like pdn_debug(pdn, "...."). What do you think?
>
> I'd switch them all to already existing dev_dbg/pci_debug rather than
> adding pdn_debug as imho it should not have been used in the first place
> really...
>
> > (I don't know exactly when edev->pdev can be NULL.)
>
> ... and if you switch to dev_dbg/pci_debug, I think quite soon you'll
> know if it can or cannot be NULL :)

As far as I can tell edev->pdev is NULL in two cases:

1. Before eeh_device_add_late() has been called on the pdev. The late
part of the add maps the pdev to an edev and sets the pdev's edev
pointer and vis a vis.
2. While recoverying EEH unaware devices. Unaware devices are
destroyed and rescanned and the edev->pdev pointer is cleared by
pcibios_device_release()

In most of these cases it should be safe to use the pci_*() functions
rather than making a new one up for printing pdns. In the cases where
we might not have a PCI dev i'd make a new set of prints that take an
EEH dev rather than a pci_dn since i'd like pci_dn to die sooner
rather than later.

Oliver