On Thu, 2017-03-09 at 16:35 -0600, Tom Lendacky wrote:
> On 3/9/2017 4:17 PM, Jeremy Linton wrote:
> > Hi,
> >
> > On 03/09/2017 03:39 PM, Tom Lendacky wrote:
> >> On 3/9/2017 3:26 PM, Jeremy Linton wrote:
> >>> Hi,
> >>
> >> Hi Jeremy,
> >>
> >> I'll have a look at it. Can you send me your kernel config just in
> >> case?
> >
> > Sure, i will send it to you off list to avoid spamming everyone with a
> > 43k gziped file.
> >
>
> I'm able to recreate the problem with my current config. If I revert
> patch 39e6c8208d7b ("net: solve a NAPI race"), then the problem goes
> away.
>
> Eric, any thoughts on this? I'm guessing the driver should check that
> napi_complete_done returns true before enabling IRQs...
>
> Thanks,
> Tom
Yes, it seems this driver has a conditional disable_irq_nosync()
following the napi_schedule_prep()
So it probably needs the same for the enable_irq() side.
This would be broken with busy polling anyway, before my patch.
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index
248f60d171a5a0ce76744a95e2d59039939e6538..c47a3a93f034ab608286d1ae343e9b7778063df8
100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
@@ -2272,9 +2272,8 @@ static int xgbe_one_poll(struct napi_struct *napi, int
budget)
processed = xgbe_rx_poll(channel, budget);
/* If we processed everything, we are done */
- if (processed < budget) {
- /* Turn off polling */
- napi_complete_done(napi, processed);
+ if (processed < budget &&
+ napi_complete_done(napi, processed)) {
/* Enable Tx and Rx interrupts */
if (pdata->channel_irq_mode)
