On Wed, 12 Dec 2007 07:20:34 -0800 (PST) David Miller <[EMAIL PROTECTED]> wrote:
> From: Stephen Hemminger <[EMAIL PROTECTED]> > Date: Tue, 11 Dec 2007 21:39:39 -0800 > > > On Wed, 12 Dec 2007 13:01:27 +0900 > > "Joonwoo Park" <[EMAIL PROTECTED]> wrote: > > > > > [NETDEV]: tehuti Fix possible causing oops of net_rx_action > > > > > > Signed-off-by: Joonwoo Park <[EMAIL PROTECTED]> > > > --- > > > drivers/net/tehuti.c | 2 ++ > > > 1 files changed, 2 insertions(+), 0 deletions(-) > > > > > > diff --git a/drivers/net/tehuti.c b/drivers/net/tehuti.c > > > index 21230c9..955e749 100644 > > > --- a/drivers/net/tehuti.c > > > +++ b/drivers/net/tehuti.c > > > @@ -305,6 +305,8 @@ static int bdx_poll(struct napi_struct *napi, int > > > budget) > > > > > > netif_rx_complete(dev, napi); > > > bdx_enable_interrupts(priv); > > > + if (unlikely(work_done == napi->weight)) > > > + return work_done - 1; > > > } > > > return work_done; > > > } > > > > A better fix would be not going over budget in the first place. > > That's not the problem. > > They are not going over the budget, rather, they are hitting > the budget yet doing netif_rx_complete() as well which is > illegal. > > Unless you strictly process less than "weight" packets, you must > not netif_rx_complete() and re-enable chip interrupts. > > I can't believe people are trying to fix this bug like this. Sorry, I was looking at a different possible problem. The issue is that if netdev_budget was set smaller (say 128) but device weight was set larger (say 256). The new code would still allow the device to do a full swipe (256) packets rather than only 128 as in earlier NAPI. I guess it is an okay behaviour change, because we don't really guarantee that case. The problem with the tehuti driver is the logic around priv->napi_stop. That whole early stop concept should be removed since it just duplicates the logic of netdev->weight but breaks the assumptions in the calling netif_rx_action. -- Stephen Hemminger <[EMAIL PROTECTED]> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
