Re: [RFC] net: napi fix

Andrew Gallatin
2007-12-12T17:30:59Z

[I apologize for loosing threading, I'm replying from the archives]

> The problem is that the driver is doing a NAPI completion and
> re-enabling chip interrupts with work_done == weight, and that is
> illegal.

The only time at least myri10ge will do this is due to
the !netif_running(netdev) check. Eg, from myri10ge's poll:

work_done = myri10ge_clean_rx_done(mgp, budget);

if (work_done < budget || !netif_running(netdev)) {
netif_rx_complete(netdev, napi);
put_be32(htonl(3), mgp->irq_claim);
}

Is the netif_running() check even required? Is this just
a bad way to solve a race with running NAPI at down() time
that would be better solved by putting a napi_synchronize()
in the driver's down() routine?

I'd rather fix this right than add another check to a
questionable code path.

Thanks,

Drew