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* [PATCH v3 01/11] net: calxedaxgmac: remove NETIF_F_FRAGLIST setting
@ 2013-08-30 21:49 Rob Herring
  2013-08-30 21:49 ` [PATCH v3 02/11] net: calxedaxgmac: read correct field in xgmac_desc_get_buf_len Rob Herring
                   ` (10 more replies)
  0 siblings, 11 replies; 15+ messages in thread
From: Rob Herring @ 2013-08-30 21:49 UTC (permalink / raw)
  To: netdev; +Cc: Ben Hutchings, Lennert Buytenhek, Rob Herring

From: Rob Herring <rob.herring@calxeda.com>

The xgmac does not actually handle frag lists, so this option should not
be set. It does not appear to have had any impact though.

Reported-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
 drivers/net/ethernet/calxeda/xgmac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c
index 7cb148c..71f6720 100644
--- a/drivers/net/ethernet/calxeda/xgmac.c
+++ b/drivers/net/ethernet/calxeda/xgmac.c
@@ -1759,7 +1759,7 @@ static int xgmac_probe(struct platform_device *pdev)
 	if (device_can_wakeup(priv->device))
 		priv->wolopts = WAKE_MAGIC;	/* Magic Frame as default */
 
-	ndev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA;
+	ndev->hw_features = NETIF_F_SG | NETIF_F_HIGHDMA;
 	if (readl(priv->base + XGMAC_DMA_HW_FEATURE) & DMA_HW_FEAT_TXCOESEL)
 		ndev->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
 				     NETIF_F_RXCSUM;
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 15+ messages in thread
* [PATCH v2 06/11] net: calxedaxgmac: fix race with tx queue stop/wake
@ 2013-08-30  3:13 Rob Herring
  2013-08-30 21:35 ` [PATCH v3 " Rob Herring
  0 siblings, 1 reply; 15+ messages in thread
From: Rob Herring @ 2013-08-30  3:13 UTC (permalink / raw)
  To: netdev; +Cc: Lennert Buytenhek, bhutchings, Rob Herring

From: Rob Herring <rob.herring@calxeda.com>

Since the xgmac transmit start and completion work locklessly, it is
possible for xgmac_xmit to stop the tx queue after the xgmac_tx_complete
has run resulting in the tx queue never being woken up. Fix this by
ensuring that ring buffer index updates are visible and recheck the ring
space after stopping the queue.

The implementation used here was copied from
drivers/net/ethernet/broadcom/tg3.c.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
v2:
- drop netif_tx_lock
- use netif_start_queue instead of netif_wake_queue

 drivers/net/ethernet/calxeda/xgmac.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c
index f630855..54be55b 100644
--- a/drivers/net/ethernet/calxeda/xgmac.c
+++ b/drivers/net/ethernet/calxeda/xgmac.c
@@ -410,6 +410,9 @@ struct xgmac_priv {
 #define dma_ring_space(h, t, s)	CIRC_SPACE(h, t, s)
 #define dma_ring_cnt(h, t, s)	CIRC_CNT(h, t, s)
 
+#define tx_dma_ring_space(p) \
+	dma_ring_space((p)->tx_head, (p)->tx_tail, DMA_TX_RING_SZ)
+
 /* XGMAC Descriptor Access Helpers */
 static inline void desc_set_buf_len(struct xgmac_dma_desc *p, u32 buf_sz)
 {
@@ -886,8 +889,10 @@ static void xgmac_tx_complete(struct xgmac_priv *priv)
 		priv->tx_tail = dma_ring_incr(entry, DMA_TX_RING_SZ);
 	}
 
-	if (dma_ring_space(priv->tx_head, priv->tx_tail, DMA_TX_RING_SZ) >
-	    MAX_SKB_FRAGS)
+	/* Ensure tx_tail is visible to xgmac_xmit */
+	smp_mb();
+	if (unlikely(netif_queue_stopped(priv->dev) &&
+	    (tx_dma_ring_space(priv) > MAX_SKB_FRAGS)))
 		netif_wake_queue(priv->dev);
 }
 
@@ -1125,10 +1130,15 @@ static netdev_tx_t xgmac_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	priv->tx_head = dma_ring_incr(entry, DMA_TX_RING_SZ);
 
-	if (dma_ring_space(priv->tx_head, priv->tx_tail, DMA_TX_RING_SZ) <
-	    MAX_SKB_FRAGS)
+	/* Ensure tx_head update is visible to tx completion */
+	smp_mb();
+	if (unlikely(tx_dma_ring_space(priv) < MAX_SKB_FRAGS)) {
 		netif_stop_queue(dev);
-
+		/* Ensure netif_stop_queue is visible to tx completion */
+		smp_mb();
+		if (tx_dma_ring_space(priv) > MAX_SKB_FRAGS)
+			netif_start_queue(dev);
+	}
 	return NETDEV_TX_OK;
 }
 
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 15+ messages in thread

end of thread, other threads:[~2013-09-04  2:22 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-08-30 21:49 [PATCH v3 01/11] net: calxedaxgmac: remove NETIF_F_FRAGLIST setting Rob Herring
2013-08-30 21:49 ` [PATCH v3 02/11] net: calxedaxgmac: read correct field in xgmac_desc_get_buf_len Rob Herring
2013-08-30 21:49 ` [PATCH v3 03/11] net: calxedaxgmac: fix race between xgmac_tx_complete and xgmac_tx_err Rob Herring
2013-08-30 21:49 ` [PATCH v3 04/11] net: calxedaxgmac: fix possible skb free before tx complete Rob Herring
2013-08-30 21:49 ` [PATCH v3 05/11] net: calxedaxgmac: update ring buffer tx_head after barriers Rob Herring
2013-08-30 21:49 ` [PATCH v3 06/11] net: calxedaxgmac: fix race with tx queue stop/wake Rob Herring
2013-08-30 22:57   ` Ben Hutchings
2013-08-30 21:49 ` [PATCH v3 07/11] net: calxedaxgmac: enable interrupts after napi_enable Rob Herring
2013-08-30 21:49 ` [PATCH v3 08/11] net: calxedaxgmac: fix various errors in xgmac_set_rx_mode Rob Herring
2013-08-30 21:49 ` [PATCH v3 09/11] net: calxedaxgmac: remove some unused statistic counters Rob Herring
2013-08-30 21:49 ` [PATCH v3 10/11] net: calxedaxgmac: fix rx DMA mapping API size mismatches Rob Herring
2013-08-30 21:49 ` [PATCH v3 11/11] net: calxedaxgmac: fix xgmac_xmit DMA mapping error handling Rob Herring
2013-09-04  2:22 ` [PATCH v3 01/11] net: calxedaxgmac: remove NETIF_F_FRAGLIST setting David Miller
  -- strict thread matches above, loose matches on Subject: below --
2013-08-30  3:13 [PATCH v2 06/11] net: calxedaxgmac: fix race with tx queue stop/wake Rob Herring
2013-08-30 21:35 ` [PATCH v3 " Rob Herring
2013-08-30 21:41   ` David Miller

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