mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-20 06:08:08 +00:00
94 lines
3.1 KiB
Diff
94 lines
3.1 KiB
Diff
From 6f152b2bdb295d86beb746494ef6fddf17986f8e Mon Sep 17 00:00:00 2001
|
|
From: John Crispin <blogic@openwrt.org>
|
|
Date: Tue, 29 Mar 2016 17:20:01 +0200
|
|
Subject: [PATCH 067/102] 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(-)
|
|
|
|
--- 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 *sk
|
|
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 *sk
|
|
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(ð->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 *sk
|
|
WRITE_ONCE(itxd->txd3, (TX_DMA_SWC | TX_DMA_PLEN0(skb_headlen(skb)) |
|
|
(!nr_frags * TX_DMA_LS0)));
|
|
|
|
- spin_unlock_irqrestore(ð->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(ð->page_lock, flags);
|
|
-
|
|
return -ENOMEM;
|
|
}
|
|
|
|
@@ -712,14 +702,22 @@ static int mtk_start_xmit(struct sk_buff
|
|
struct mtk_eth *eth = mac->hw;
|
|
struct mtk_tx_ring *ring = ð->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(ð->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(ð->page_lock, flags);
|
|
return NETDEV_TX_BUSY;
|
|
}
|
|
|
|
@@ -747,10 +745,12 @@ static int mtk_start_xmit(struct sk_buff
|
|
ring->thresh))
|
|
mtk_wake_queue(eth);
|
|
}
|
|
+ spin_unlock_irqrestore(ð->page_lock, flags);
|
|
|
|
return NETDEV_TX_OK;
|
|
|
|
drop:
|
|
+ spin_unlock_irqrestore(ð->page_lock, flags);
|
|
stats->tx_dropped++;
|
|
dev_kfree_skb(skb);
|
|
return NETDEV_TX_OK;
|