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Commit 2c2a9cbd authored by Karl Beldan's avatar Karl Beldan Committed by David S. Miller
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net: mv643xx_eth: reclaim TX skbs only when released by the HW 



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: 3ae8f4e0 ('net: mv643xx_eth: Implement software TSO')
Reported-by: default avatarSlawomir Gajzner <slawomir.gajzner@gmail.com>
Reported-by: default avatarJulien D'Ascenzio <jdascenzio@yahoo.fr>
Signed-off-by: default avatarKarl 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: default avatarDavid S. Miller <davem@davemloft.net>
parent 66f1c448

drivers/net/ethernet/marvell/mv643xx_eth.c

+10 −8
Original line number Diff line number Diff line
@@ -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);