On Fri, 2018-03-23 at 17:33 +1100, Benjamin Herrenschmidt wrote:
> On Fri, 2018-03-23 at 16:44 +1100, Michael Neuling wrote:
>
> .../...
>
> > This fixes the problem in the same way the generic PCIe AER code (in
> > drivers/pci/pcie/aer/aerdrv_core.c) does. It makes the EEH code hold
> > the device_lock() before performing the driver EEH callbacks. This
> > ensures either the callbacks are no longer register, or if they are
> > registered the driver will not be removed from underneath us.
> >
> > Signed-off-by: Michael Neuling <mi...@neuling.org>
>
> Generally ok, minor nits though and do we want a CC stable ?
ok, I'll cc stable.
>
> > ---
> > arch/powerpc/kernel/eeh_driver.c | 67 ++++++++++++++++++++++++-------------
> > ---
> > 1 file changed, 41 insertions(+), 26 deletions(-)
> >
> > diff --git a/arch/powerpc/kernel/eeh_driver.c
> > b/arch/powerpc/kernel/eeh_driver.c
> > index 0c0b66fc5b..7cf946ae9a 100644
> > --- a/arch/powerpc/kernel/eeh_driver.c
> > +++ b/arch/powerpc/kernel/eeh_driver.c
> > @@ -207,18 +207,18 @@ static void *eeh_report_error(void *data, void
> > *userdata)
> >
> > if (!dev || eeh_dev_removed(edev) || eeh_pe_passed(edev->pe))
> > return NULL;
> > +
> > + device_lock(&dev->dev);
> > dev->error_state = pci_channel_io_frozen;
> >
> > driver = eeh_pcid_get(dev);
> > - if (!driver) return NULL;
> > + if (!driver) goto out2;
>
> I don't like out1/out2, why not call them out_nodev and out_no_handler
> ? (same comment for the other ones).
OK, will change.
> >
> > eeh_disable_irq(dev);
> >
> > if (!driver->err_handler ||
> > - !driver->err_handler->error_detected) {
> > - eeh_pcid_put(dev);
> > - return NULL;
> > - }
> > + !driver->err_handler->error_detected)
> > + goto out1;
> >
> > rc = driver->err_handler->error_detected(dev,
> > pci_channel_io_frozen);
> >
> > @@ -227,8 +227,11 @@ static void *eeh_report_error(void *data, void
> > *userdata)
> > if (*res == PCI_ERS_RESULT_NONE) *res = rc;
> >
> > edev->in_error = true;
> > - eeh_pcid_put(dev);
> > pci_uevent_ers(dev, PCI_ERS_RESULT_NONE);
> > +out1:
> > + eeh_pcid_put(dev);
> > +out2:
>
> This also changes doing the uevent while holding a reference and the
> the device lock, is that ok ? (I guess a reference is a good thing, the
> device lock, not sure... I hope so but you should at least document it
> as a chance in the cset comment).
The AER code does this, so it should be ok. See report_error_detected().
Mikey
