mediatek: update patches

[openwrt/svn-archive/archive.git] / target / linux / mediatek / patches-4.4 / 0071-net-mediatek-fix-TX-locking.patch

diff --git a/target/linux/mediatek/patches-4.4/0071-net-mediatek-fix-TX-locking.patch b/target/linux/mediatek/patches-4.4/0071-net-mediatek-fix-TX-locking.patch
new file mode 100644 (file)
index 0000000..011fad2
--- /dev/null
+++ b/target/linux/mediatek/patches-4.4/0071-net-mediatek-fix-TX-locking.patch
@@ -0,0 +1,98 @@
+From b9df14f712866925856c0ffb2d899511c21e1b8a Mon Sep 17 00:00:00 2001
+From: John Crispin <blogic@openwrt.org>
+Date: Tue, 29 Mar 2016 17:20:01 +0200
+Subject: [PATCH 71/78] net: mediatek: fix TX locking
+
+Inside the TX path there is a lock inside the tx_map function. This is
+however too late. The patch moves the lock to the start of the xmit
+function right before the free count check of the DMA ring happens.
+If we do not do this, the code becomes racy leading to TX stalls and
+dropped packets. This happens as there are 2 netdevs running on the
+same physical DMA ring.
+
+Signed-off-by: John Crispin <blogic@openwrt.org>
+---
+ drivers/net/ethernet/mediatek/mtk_eth_soc.c |   20 ++++++++++----------
+ 1 file changed, 10 insertions(+), 10 deletions(-)
+
+diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+index 26eeb1a..67b18f9 100644
+--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
++++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+@@ -536,7 +536,6 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
+       struct mtk_eth *eth = mac->hw;
+       struct mtk_tx_dma *itxd, *txd;
+       struct mtk_tx_buf *tx_buf;
+-      unsigned long flags;
+       dma_addr_t mapped_addr;
+       unsigned int nr_frags;
+       int i, n_desc = 1;
+@@ -568,11 +567,6 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
+       if (unlikely(dma_mapping_error(&dev->dev, mapped_addr)))
+               return -ENOMEM;
+ 
+-      /* normally we can rely on the stack not calling this more than once,
+-       * however we have 2 queues running ont he same ring so we need to lock
+-       * the ring access
+-       */
+-      spin_lock_irqsave(&eth->page_lock, flags);
+       WRITE_ONCE(itxd->txd1, mapped_addr);
+       tx_buf->flags |= MTK_TX_FLAGS_SINGLE0;
+       dma_unmap_addr_set(tx_buf, dma_addr0, mapped_addr);
+@@ -632,8 +626,6 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
+       WRITE_ONCE(itxd->txd3, (TX_DMA_SWC | TX_DMA_PLEN0(skb_headlen(skb)) |
+                               (!nr_frags * TX_DMA_LS0)));
+ 
+-      spin_unlock_irqrestore(&eth->page_lock, flags);
+-
+       netdev_sent_queue(dev, skb->len);
+       skb_tx_timestamp(skb);
+ 
+@@ -661,8 +653,6 @@ err_dma:
+               itxd = mtk_qdma_phys_to_virt(ring, itxd->txd2);
+       } while (itxd != txd);
+ 
+-      spin_unlock_irqrestore(&eth->page_lock, flags);
+-
+       return -ENOMEM;
+ }
+ 
+@@ -712,14 +702,22 @@ static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
+       struct mtk_eth *eth = mac->hw;
+       struct mtk_tx_ring *ring = &eth->tx_ring;
+       struct net_device_stats *stats = &dev->stats;
++      unsigned long flags;
+       bool gso = false;
+       int tx_num;
+ 
++      /* normally we can rely on the stack not calling this more than once,
++       * however we have 2 queues running ont he same ring so we need to lock
++       * the ring access
++       */
++      spin_lock_irqsave(&eth->page_lock, flags);
++
+       tx_num = mtk_cal_txd_req(skb);
+       if (unlikely(atomic_read(&ring->free_count) <= tx_num)) {
+               mtk_stop_queue(eth);
+               netif_err(eth, tx_queued, dev,
+                         "Tx Ring full when queue awake!\n");
++              spin_unlock_irqrestore(&eth->page_lock, flags);
+               return NETDEV_TX_BUSY;
+       }
+ 
+@@ -747,10 +745,12 @@ static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
+                            ring->thresh))
+                       mtk_wake_queue(eth);
+       }
++      spin_unlock_irqrestore(&eth->page_lock, flags);
+ 
+       return NETDEV_TX_OK;
+ 
+ drop:
++      spin_unlock_irqrestore(&eth->page_lock, flags);
+       stats->tx_dropped++;
+       dev_kfree_skb(skb);
+       return NETDEV_TX_OK;
+-- 
+1.7.10.4
+