Messages in this thread | | | Date | Mon, 12 Apr 2010 08:38:42 -0700 | From | Stephen Hemminger <> | Subject | Re: [Bonding-devel] [v3 Patch 2/3] bridge: make bridge support netpoll |
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On Mon, 12 Apr 2010 12:38:57 +0200 Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Le lundi 12 avril 2010 à 18:37 +0800, Cong Wang a écrit : > > Stephen Hemminger wrote: > > > There is no protection on dev->priv_flags for SMP access. > > > It would better bit value in dev->state if you are using it as control flag. > > > > > > Then you could use > > > if (unlikely(test_and_clear_bit(__IN_NETPOLL, &skb->dev->state))) > > > netpoll_send_skb(...) > > > > > > > > > > Hmm, I think we can't use ->state here, it is not for this kind of purpose, > > according to its comments. > > > > Also, I find other usages of IFF_XXX flags of ->priv_flags are also using > > &, | to set or clear the flags. So there must be some other things preventing > > the race... > > Yes, its RTNL that protects priv_flags changes, hopefully... >
The patch was not protecting priv_flags with RTNL. For example..
@@ -308,7 +312,9 @@ static void netpoll_send_skb(struct netp tries > 0; --tries) { if (__netif_tx_trylock(txq)) { if (!netif_tx_queue_stopped(txq)) { + dev->priv_flags |= IFF_IN_NETPOLL; status = ops->ndo_start_xmit(skb, dev); + dev->priv_flags &= ~IFF_IN_NETPOLL; if (status == NETDEV_TX_OK) txq_trans_update(txq); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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