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authorDivy Le Ray <divy@chelsio.com>2008-03-13 00:13:30 -0700
committerJeff Garzik <jeff@garzik.org>2008-03-17 08:07:01 -0400
commitcd7e903440bad2625afa4090f34bf497593656cd (patch)
treefd718ac8012aa60ad855556bc0caa903fe69ac4c
parentcdb346977829885cbd8b1200ca21049b1df242ad (diff)
cxgb3: Fix transmit queue stop mechanism
The last change in the Tx queue stop mechanism opens a window where the Tx queue might be stopped after pending credits returned. Tx credits are returned via a control message generated by the HW. It returns tx credits on demand, triggered by a completion bit set in selective transmit packet headers. The current code can lead to the Tx queue stopped with all pending credits returned, and the current frame not triggering a credit return. The Tx queue will then never be awaken. The driver could alternatively request a completion for packets that stop the queue. It's however safer at this point to go back to the pre-existing behaviour. Signed-off-by: Divy Le Ray <divy@chelsio.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
-rw-r--r--drivers/net/cxgb3/sge.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index 979f3fc5e76..db586870c5f 100644
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -1107,9 +1107,15 @@ int t3_eth_xmit(struct sk_buff *skb, struct net_device *dev)
}
q->in_use += ndesc;
- if (unlikely(credits - ndesc < q->stop_thres))
- if (USE_GTS || !should_restart_tx(q))
- t3_stop_queue(dev, qs, q);
+ if (unlikely(credits - ndesc < q->stop_thres)) {
+ t3_stop_queue(dev, qs, q);
+
+ if (should_restart_tx(q) &&
+ test_and_clear_bit(TXQ_ETH, &qs->txq_stopped)) {
+ q->restarts++;
+ netif_wake_queue(dev);
+ }
+ }
gen = q->gen;
q->unacked += ndesc;