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Commit b9b39b62 authored by Ben Hutchings's avatar Ben Hutchings Committed by Jeff Garzik
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[netdrvr] sfc: Add TSO support 



The SFC4000 controller does not have hardware support for TSO, and the
core GSO code incurs a high cost in allocating and freeing skbs.  This
TSO implementation uses lightweight packet header structures and is
substantially faster.

Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 48cfb14f

drivers/net/sfc/efx.c

+3 −1
Original line number Diff line number Diff line
@@ -1873,6 +1873,7 @@ static int efx_init_struct(struct efx_nic *efx, struct efx_nic_type *type, 
		tx_queue->queue = i;

		tx_queue->buffer = NULL;

		tx_queue->channel = &efx->channel[0]; /* for safety */

		tx_queue->tso_headers_free = NULL;

	}

	for (i = 0; i < EFX_MAX_RX_QUEUES; i++) {

		rx_queue = &efx->rx_queue[i];
@@ -2071,7 +2072,8 @@ static int __devinit efx_pci_probe(struct pci_dev *pci_dev, 
	net_dev = alloc_etherdev(sizeof(*efx));

	if (!net_dev)

		return -ENOMEM;

	net_dev->features |= NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_HIGHDMA;

	net_dev->features |= (NETIF_F_IP_CSUM | NETIF_F_SG |

			      NETIF_F_HIGHDMA | NETIF_F_TSO);

	if (lro)

		net_dev->features |= NETIF_F_LRO;

	efx = net_dev->priv;

drivers/net/sfc/ethtool.c

+27 −0
Original line number Diff line number Diff line
@@ -272,6 +272,22 @@ static void efx_ethtool_get_stats(struct net_device *net_dev, 
	}

}



static int efx_ethtool_set_tso(struct net_device *net_dev, u32 enable)

{

	int rc;



	/* Our TSO requires TX checksumming, so force TX checksumming

	 * on when TSO is enabled.

	 */

	if (enable) {

		rc = efx_ethtool_set_tx_csum(net_dev, 1);

		if (rc)

			return rc;

	}



	return ethtool_op_set_tso(net_dev, enable);

}



static int efx_ethtool_set_tx_csum(struct net_device *net_dev, u32 enable)

{

	struct efx_nic *efx = net_dev->priv;
@@ -283,6 +299,15 @@ static int efx_ethtool_set_tx_csum(struct net_device *net_dev, u32 enable) 


	efx_flush_queues(efx);



	/* Our TSO requires TX checksumming, so disable TSO when

	 * checksumming is disabled

	 */

	if (!enable) {

		rc = efx_ethtool_set_tso(net_dev, 0);

		if (rc)

			return rc;

	}



	return 0;

}
@@ -451,6 +476,8 @@ struct ethtool_ops efx_ethtool_ops = { 
	.set_tx_csum		= efx_ethtool_set_tx_csum,

	.get_sg			= ethtool_op_get_sg,

	.set_sg			= ethtool_op_set_sg,

	.get_tso		= ethtool_op_get_tso,

	.set_tso		= efx_ethtool_set_tso,

	.get_flags		= ethtool_op_get_flags,

	.set_flags		= ethtool_op_set_flags,

	.get_strings		= efx_ethtool_get_strings,

drivers/net/sfc/net_driver.h

+14 −0
Original line number Diff line number Diff line
@@ -134,6 +134,8 @@ struct efx_special_buffer { 
 *	Set only on the final fragment of a packet; %NULL for all other

 *	fragments.  When this fragment completes, then we can free this

 *	skb.

 * @tsoh: The associated TSO header structure, or %NULL if this

 *	buffer is not a TSO header.

 * @dma_addr: DMA address of the fragment.

 * @len: Length of this fragment.

 *	This field is zero when the queue slot is empty.
@@ -144,6 +146,7 @@ struct efx_special_buffer { 
 */

struct efx_tx_buffer {

	const struct sk_buff *skb;

	struct efx_tso_header *tsoh;

	dma_addr_t dma_addr;

	unsigned short len;

	unsigned char continuation;
@@ -187,6 +190,13 @@ struct efx_tx_buffer { 
 *	variable indicates that the queue is full.  This is to

 *	avoid cache-line ping-pong between the xmit path and the

 *	completion path.

 * @tso_headers_free: A list of TSO headers allocated for this TX queue

 *	that are not in use, and so available for new TSO sends. The list

 *	is protected by the TX queue lock.

 * @tso_bursts: Number of times TSO xmit invoked by kernel

 * @tso_long_headers: Number of packets with headers too long for standard

 *	blocks

 * @tso_packets: Number of packets via the TSO xmit path

 */

struct efx_tx_queue {

	/* Members which don't change on the fast path */
@@ -206,6 +216,10 @@ struct efx_tx_queue { 
	unsigned int insert_count ____cacheline_aligned_in_smp;

	unsigned int write_count;

	unsigned int old_read_count;

	struct efx_tso_header *tso_headers_free;

	unsigned int tso_bursts;

	unsigned int tso_long_headers;

	unsigned int tso_packets;

};



/**

drivers/net/sfc/tx.c

+664 −0

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