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net: mv643xx_eth: reclaim TX skbs only when released by the HW

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ATM, txq_reclaim will dequeue and free an skb for each tx desc released
by the hw that has TX_LAST_DESC set. However, in case of TSO, each
hw desc embedding the last part of a segment has TX_LAST_DESC set,
losing the one-to-one 'last skb frag'/'TX_LAST_DESC set' correspondance,
which causes data corruption.

Fix this by checking TX_ENABLE_INTERRUPT instead of TX_LAST_DESC, and
warn when trying to dequeue from an empty txq (which can be symptomatic
of releasing skbs prematurely).

Fixes: 3ae8f4e0b9 ('net: mv643xx_eth: Implement software TSO')
Reported-by: Slawomir Gajzner <slawomir.gajzner@gmail.com>
Reported-by: Julien D'Ascenzio <jdascenzio@yahoo.fr>
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Cc: Ian Campbell <ijc@hellion.org.uk>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Karl Beldan 2014-11-05 15:32:59 +01:00 committed by David S. Miller
parent 66f1c44887
commit 2c2a9cbd64
1 changed files with 10 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/net/ethernet/marvell/mv643xx_eth.c
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@ -1047,7 +1047,6 @@ static int txq_reclaim(struct tx_queue *txq, int budget, int force)
int tx_index;
struct tx_desc *desc;
u32 cmd_sts;
struct sk_buff *skb;
tx_index = txq->tx_used_desc;
desc = &txq->tx_desc_area[tx_index];
@ -1066,19 +1065,22 @@ static int txq_reclaim(struct tx_queue *txq, int budget, int force)
reclaimed++;
txq->tx_desc_count--;
skb = NULL;
if (cmd_sts & TX_LAST_DESC)
skb = __skb_dequeue(&txq->tx_skb);
if (!IS_TSO_HEADER(txq, desc->buf_ptr))
dma_unmap_single(mp->dev->dev.parent, desc->buf_ptr,
desc->byte_cnt, DMA_TO_DEVICE);
if (cmd_sts & TX_ENABLE_INTERRUPT) {
struct sk_buff *skb = __skb_dequeue(&txq->tx_skb);
if (!WARN_ON(!skb))
dev_kfree_skb(skb);
}
if (cmd_sts & ERROR_SUMMARY) {
netdev_info(mp->dev, "tx error\n");
mp->dev->stats.tx_errors++;
}
if (!IS_TSO_HEADER(txq, desc->buf_ptr))
dma_unmap_single(mp->dev->dev.parent, desc->buf_ptr,
desc->byte_cnt, DMA_TO_DEVICE);
dev_kfree_skb(skb);
}
__netif_tx_unlock_bh(nq);