From: Anton Vorontsov <avorontsov@ru•mvista.com>
To: David Miller <davem@davemloft•net>
Cc: linuxppc-dev@ozlabs•org, netdev@vger•kernel.org,
Wu Jiajun-B06378 <B06378@freescale•com>,
lsorense@csclub•uwaterloo.ca
Subject: [PATCH] ucc_geth: Fix full TX queue processing
Date: Mon, 18 Jan 2010 18:47:50 +0300 [thread overview]
Message-ID: <20100118154750.GA9224@oksana.dev.rtsoft.ru> (raw)
From: Jiajun Wu <b06378@freescale•com>
commit 7583605b6d29f1f7f6fc505b883328089f3485ad ("ucc_geth: Fix empty
TX queue processing") fixed empty TX queue mishandling, but didn't
account another corner case: when TX queue becomes full.
Without this patch the driver will stop transmiting when TX queue
becomes full since 'bd == ugeth->txBd[txQ]' actually checks for
two things: queue empty or full.
Let's better check for NULL skb, which unambiguously signals an empty
queue.
Signed-off-by: Jiajun Wu <b06378@freescale•com>
Signed-off-by: Anton Vorontsov <avorontsov@ru•mvista.com>
Cc: Stable <stable@vger•kernel.org> [2.6.32]
---
On Mon, Jan 11, 2010 at 07:52:26PM +0800, Wu Jiajun-B06378 wrote:
> 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.
OK, let's resend the patch with just !skb check?
drivers/net/ucc_geth.c | 5 ++---
1 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index 96bdc0b..eb8fe7e 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 +
--
1.6.5.7
next reply other threads:[~2010-01-18 15:47 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-18 15:47 Anton Vorontsov [this message]
2010-01-19 10:00 ` [PATCH] ucc_geth: Fix full TX queue processing David Miller
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