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Commit 2367a173 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

ixgbe: flush when in xmit_more mode and under descriptor pressure 



When xmit_more mode is being used and the ring is about to
become full or the stack has stopped the ring, enforce a tail
pointer write to the hw. Otherwise, we could risk a TX hang.

Code suggested by Alexander Duyck.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 900405d0

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

+34 −29
Original line number Original line Diff line number Diff line
@@ -6837,6 +6837,36 @@ static void ixgbe_tx_olinfo_status(union ixgbe_adv_tx_desc *tx_desc, 
	tx_desc->read.olinfo_status = cpu_to_le32(olinfo_status);

	tx_desc->read.olinfo_status = cpu_to_le32(olinfo_status);

}

}





static int __ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size)

{

	netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index);



	/* Herbert's original patch had:

	 *  smp_mb__after_netif_stop_queue();

	 * but since that doesn't exist yet, just open code it.

	 */

	smp_mb();



	/* We need to check again in a case another CPU has just

	 * made room available.

	 */

	if (likely(ixgbe_desc_unused(tx_ring) < size))

		return -EBUSY;



	/* A reprieve! - use start_queue because it doesn't call schedule */

	netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index);

	++tx_ring->tx_stats.restart_queue;

	return 0;

}



static inline int ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size)

{

	if (likely(ixgbe_desc_unused(tx_ring) >= size))

		return 0;



	return __ixgbe_maybe_stop_tx(tx_ring, size);

}



#define IXGBE_TXD_CMD (IXGBE_TXD_CMD_EOP | \

#define IXGBE_TXD_CMD (IXGBE_TXD_CMD_EOP | \

		       IXGBE_TXD_CMD_RS)

		       IXGBE_TXD_CMD_RS)
@@ -6958,10 +6988,13 @@ static void ixgbe_tx_map(struct ixgbe_ring *tx_ring, 




	tx_ring->next_to_use = i;

	tx_ring->next_to_use = i;





	if (!skb->xmit_more) {

	ixgbe_maybe_stop_tx(tx_ring, DESC_NEEDED);



	if (netif_xmit_stopped(txring_txq(tx_ring)) || !skb->xmit_more) {

		/* notify HW of packet */

		/* notify HW of packet */

		ixgbe_write_tail(tx_ring, i);

		ixgbe_write_tail(tx_ring, i);

	}

	}



	return;

	return;

dma_error:

dma_error:

	dev_err(tx_ring->dev, "TX DMA map failed\n");

	dev_err(tx_ring->dev, "TX DMA map failed\n");
@@ -7068,32 +7101,6 @@ static void ixgbe_atr(struct ixgbe_ring *ring, 
					      input, common, ring->queue_index);

					      input, common, ring->queue_index);

}

}





static int __ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size)

{

	netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index);

	/* Herbert's original patch had:

	 *  smp_mb__after_netif_stop_queue();

	 * but since that doesn't exist yet, just open code it. */

	smp_mb();



	/* We need to check again in a case another CPU has just

	 * made room available. */

	if (likely(ixgbe_desc_unused(tx_ring) < size))

		return -EBUSY;



	/* A reprieve! - use start_queue because it doesn't call schedule */

	netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index);

	++tx_ring->tx_stats.restart_queue;

	return 0;

}



static inline int ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size)

{

	if (likely(ixgbe_desc_unused(tx_ring) >= size))

		return 0;

	return __ixgbe_maybe_stop_tx(tx_ring, size);

}



static u16 ixgbe_select_queue(struct net_device *dev, struct sk_buff *skb,

static u16 ixgbe_select_queue(struct net_device *dev, struct sk_buff *skb,

			      void *accel_priv, select_queue_fallback_t fallback)

			      void *accel_priv, select_queue_fallback_t fallback)

{

{
@@ -7262,8 +7269,6 @@ netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *skb, 
#endif /* IXGBE_FCOE */

#endif /* IXGBE_FCOE */

	ixgbe_tx_map(tx_ring, first, hdr_len);

	ixgbe_tx_map(tx_ring, first, hdr_len);





	ixgbe_maybe_stop_tx(tx_ring, DESC_NEEDED);



	return NETDEV_TX_OK;

	return NETDEV_TX_OK;





out_drop:

out_drop: