Yes,'if (!skb)' is enough. You can reproduce transmitting stopping if you use 'if ((bd == ugeth->txBd[txQ])' and run ipforwarding with MTU=64 1Gbps 100%linerate.
-----Original Message----- From: Anton Vorontsov [mailto:avoront...@ru.mvista.com] Sent: 2010年1月11日 18:53 To: Wu Jiajun-B06378 Cc: linuxppc-...@ozlabs.org; net...@vger.kernel.org; lsore...@csclub.uwaterloo.ca; da...@davemloft.net Subject: Re: [PATCH 1/3] ucc_geth: Fix empty TX queue processing On Mon, Jan 11, 2010 at 11:47:37AM +0800, Wu Jiajun-B06378 wrote: > > 'bd == ugeth->txBd[txQ]' has two possible statuses: 1)full queue. > 2)empty queue. > Removing 'netif_queue_stopped() == 0' will make transmitting stopping > when the queue is full. > > I made a new patch for this oops. [...] > + if ((bd == ugeth->txBd[txQ]) && (skb == NULL)) > break; Hm. I wonder why do we need the 'bd == ugeth->txBd[txQ]' check at all? The null skb will cause a kernel oops anyway. I think the patch below should be sufficient for the fix. Can you try it? Or if you tell me how to reproduce the issue you observe, I can try it myself. Thanks a lot! diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c index 41ad2f3..a1a6d06 100644 --- a/drivers/net/ucc_geth.c +++ b/drivers/net/ucc_geth.c @@ -3279,13 +3279,12 @@ static int ucc_geth_tx(struct net_device *dev, u8 txQ) /* Handle the transmitted buffer and release */ /* the BD to be used with the current frame */ - if (bd == ugeth->txBd[txQ]) /* queue empty? */ + skb = ugeth->tx_skbuff[txQ][ugeth->skb_dirtytx[txQ]]; + if (!skb) break; dev->stats.tx_packets++; - skb = ugeth->tx_skbuff[txQ][ugeth->skb_dirtytx[txQ]]; - if (skb_queue_len(&ugeth->rx_recycle) < RX_BD_RING_LEN && skb_recycle_check(skb, ugeth->ug_info->uf_info.max_rx_buf_length + _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
