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qeth: exploit HW TX checksumming
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OSA supports HW TX checksumming in layer 3 mode. Enable this
feature and remove software fallback used for TSO. Cleanup
checksum bits to indicate OSA can do checksumming only for
IPv4 TCP and UDP.

Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Frank Blaschka authored and David S. Miller committed May 16, 2010
1 parent 2d6c9ff commit f6b85b6
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Showing 2 changed files with 69 additions and 26 deletions.
3 changes: 2 additions & 1 deletion drivers/s390/net/qeth_core.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -351,7 +351,7 @@ enum qeth_header_ids {
#define QETH_HDR_EXT_SRC_MAC_ADDR 0x08
#define QETH_HDR_EXT_CSUM_HDR_REQ 0x10
#define QETH_HDR_EXT_CSUM_TRANSP_REQ 0x20
#define QETH_HDR_EXT_UDP_TSO 0x40 /*bit off for TCP*/
#define QETH_HDR_EXT_UDP 0x40 /*bit off for TCP*/

static inline int qeth_is_last_sbale(struct qdio_buffer_element *sbale)
{
Expand Down Expand Up @@ -630,6 +630,7 @@ struct qeth_card_info {
int unique_id;
struct qeth_card_blkt blkt;
__u32 csum_mask;
__u32 tx_csum_mask;
enum qeth_ipa_promisc_modes promisc_mode;
};

Expand Down
92 changes: 67 additions & 25 deletions drivers/s390/net/qeth_l3_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -54,16 +54,16 @@ int qeth_l3_set_large_send(struct qeth_card *card,
if (card->options.large_send == QETH_LARGE_SEND_TSO) {
if (qeth_is_supported(card, IPA_OUTBOUND_TSO)) {
card->dev->features |= NETIF_F_TSO | NETIF_F_SG |
NETIF_F_HW_CSUM;
NETIF_F_IP_CSUM;
} else {
card->dev->features &= ~(NETIF_F_TSO | NETIF_F_SG |
NETIF_F_HW_CSUM);
NETIF_F_IP_CSUM);
card->options.large_send = QETH_LARGE_SEND_NO;
rc = -EOPNOTSUPP;
}
} else {
card->dev->features &= ~(NETIF_F_TSO | NETIF_F_SG |
NETIF_F_HW_CSUM);
NETIF_F_IP_CSUM);
card->options.large_send = QETH_LARGE_SEND_NO;
}
return rc;
Expand Down Expand Up @@ -1108,6 +1108,13 @@ static int qeth_l3_default_setassparms_cb(struct qeth_card *card,
card->info.csum_mask = cmd->data.setassparms.data.flags_32bit;
QETH_DBF_TEXT_(TRACE, 3, "csum:%d", card->info.csum_mask);
}
if (cmd->data.setassparms.hdr.assist_no == IPA_OUTBOUND_CHECKSUM &&
cmd->data.setassparms.hdr.command_code == IPA_CMD_ASS_START) {
card->info.tx_csum_mask =
cmd->data.setassparms.data.flags_32bit;
QETH_DBF_TEXT_(TRACE, 3, "tcsu:%d", card->info.tx_csum_mask);
}

return 0;
}

Expand Down Expand Up @@ -1536,6 +1543,28 @@ static int qeth_l3_start_ipa_checksum(struct qeth_card *card)
return rc;
}

static int qeth_l3_start_ipa_tx_checksum(struct qeth_card *card)
{
int rc = 0;

if (!qeth_is_supported(card, IPA_OUTBOUND_CHECKSUM))
return rc;
rc = qeth_l3_send_simple_setassparms(card, IPA_OUTBOUND_CHECKSUM,
IPA_CMD_ASS_START, 0);
if (rc)
goto err_out;
rc = qeth_l3_send_simple_setassparms(card, IPA_OUTBOUND_CHECKSUM,
IPA_CMD_ASS_ENABLE, card->info.tx_csum_mask);
if (rc)
goto err_out;
dev_info(&card->gdev->dev, "HW TX Checksumming enabled\n");
return rc;
err_out:
dev_warn(&card->gdev->dev, "Enabling HW TX checksumming for %s "
"failed, using SW TX checksumming\n", QETH_CARD_IFNAME(card));
return rc;
}

static int qeth_l3_start_ipa_tso(struct qeth_card *card)
{
int rc;
Expand Down Expand Up @@ -1578,6 +1607,7 @@ static int qeth_l3_start_ipassists(struct qeth_card *card)
qeth_l3_start_ipa_ipv6(card); /* go on*/
qeth_l3_start_ipa_broadcast(card); /* go on*/
qeth_l3_start_ipa_checksum(card); /* go on*/
qeth_l3_start_ipa_tx_checksum(card);
qeth_l3_start_ipa_tso(card); /* go on*/
return 0;
}
Expand Down Expand Up @@ -2817,6 +2847,21 @@ static void qeth_l3_fill_header(struct qeth_card *card, struct qeth_hdr *hdr,
}
}

static inline void qeth_l3_hdr_csum(struct qeth_card *card,
struct qeth_hdr *hdr, struct sk_buff *skb)
{
struct iphdr *iph = ip_hdr(skb);

/* tcph->check contains already the pseudo hdr checksum
* so just set the header flags
*/
if (iph->protocol == IPPROTO_UDP)
hdr->hdr.l3.ext_flags |= QETH_HDR_EXT_UDP;
hdr->hdr.l3.ext_flags |= QETH_HDR_EXT_CSUM_TRANSP_REQ;
if (card->options.performance_stats)
card->perf_stats.tx_csum++;
}

static void qeth_tso_fill_header(struct qeth_card *card,
struct qeth_hdr *qhdr, struct sk_buff *skb)
{
Expand Down Expand Up @@ -2852,21 +2897,6 @@ static void qeth_tso_fill_header(struct qeth_card *card,
}
}

static void qeth_tx_csum(struct sk_buff *skb)
{
__wsum csum;
int offset;

skb_set_transport_header(skb, skb->csum_start - skb_headroom(skb));
offset = skb->csum_start - skb_headroom(skb);
BUG_ON(offset >= skb_headlen(skb));
csum = skb_checksum(skb, offset, skb->len - offset, 0);

offset += skb->csum_offset;
BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb));
*(__sum16 *)(skb->data + offset) = csum_fold(csum);
}

static inline int qeth_l3_tso_elements(struct sk_buff *skb)
{
unsigned long tcpd = (unsigned long)tcp_hdr(skb) +
Expand Down Expand Up @@ -2923,12 +2953,6 @@ static int qeth_l3_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)

if (skb_is_gso(skb))
large_send = card->options.large_send;
else
if (skb->ip_summed == CHECKSUM_PARTIAL) {
qeth_tx_csum(skb);
if (card->options.performance_stats)
card->perf_stats.tx_csum++;
}

if ((card->info.type == QETH_CARD_TYPE_IQD) && (!large_send) &&
(skb_shinfo(skb)->nr_frags == 0)) {
Expand Down Expand Up @@ -3007,6 +3031,9 @@ static int qeth_l3_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
cast_type);
hdr->hdr.l3.length = new_skb->len - data_offset;
}

if (skb->ip_summed == CHECKSUM_PARTIAL)
qeth_l3_hdr_csum(card, hdr, new_skb);
}

elems = qeth_get_elements_no(card, (void *)hdr, new_skb,
Expand Down Expand Up @@ -3132,10 +3159,25 @@ static int qeth_l3_ethtool_set_tso(struct net_device *dev, u32 data)
return rc;
}

static int qeth_l3_ethtool_set_tx_csum(struct net_device *dev, u32 data)
{
struct qeth_card *card = dev->ml_priv;

if (data) {
if (qeth_is_supported(card, IPA_OUTBOUND_CHECKSUM))
dev->features |= NETIF_F_IP_CSUM;
else
return -EPERM;
} else
dev->features &= ~NETIF_F_IP_CSUM;

return 0;
}

static const struct ethtool_ops qeth_l3_ethtool_ops = {
.get_link = ethtool_op_get_link,
.get_tx_csum = ethtool_op_get_tx_csum,
.set_tx_csum = ethtool_op_set_tx_hw_csum,
.set_tx_csum = qeth_l3_ethtool_set_tx_csum,
.get_rx_csum = qeth_l3_ethtool_get_rx_csum,
.set_rx_csum = qeth_l3_ethtool_set_rx_csum,
.get_sg = ethtool_op_get_sg,
Expand Down

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