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lan78xx: Remove hardware-specific header update
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Remove hardware-specific header length adjustment as it is no longer
required. It also breaks generic receive offload (GRO) processing of
received TCP frames that results in a TCP ACK being sent for each
received frame.

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@jefstath @davem330
jefstath authored and davem330 committed Nov 18, 2021
1 parent 9d2da72 commit 0dd8726
Showing 1 changed file with 16 additions and 35 deletions.
51 changes: 16 additions & 35 deletions drivers/net/usb/lan78xx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,6 @@
#define DEFAULT_TSO_CSUM_ENABLE (true)
#define DEFAULT_VLAN_FILTER_ENABLE (true)
#define DEFAULT_VLAN_RX_OFFLOAD (true)
#define TX_OVERHEAD (8)
#define TX_ALIGNMENT (4)
#define RXW_PADDING 2

Expand Down Expand Up @@ -120,6 +119,10 @@
#define TX_SKB_MIN_LEN (TX_CMD_LEN + ETH_HLEN)
#define LAN78XX_TSO_SIZE(dev) ((dev)->tx_urb_size - TX_SKB_MIN_LEN)

#define RX_CMD_LEN 10
#define RX_SKB_MIN_LEN (RX_CMD_LEN + ETH_HLEN)
#define RX_MAX_FRAME_LEN(mtu) ((mtu) + ETH_HLEN + VLAN_HLEN)

/* USB related defines */
#define BULK_IN_PIPE 1
#define BULK_OUT_PIPE 2
Expand Down Expand Up @@ -440,8 +443,6 @@ struct lan78xx_net {
struct mutex phy_mutex; /* for phy access */
unsigned int pipe_in, pipe_out, pipe_intr;

u32 hard_mtu; /* count any extra framing */

unsigned int bulk_in_delay;
unsigned int burst_cap;

Expand Down Expand Up @@ -2536,37 +2537,24 @@ static int unlink_urbs(struct lan78xx_net *dev, struct sk_buff_head *q)
static int lan78xx_change_mtu(struct net_device *netdev, int new_mtu)
{
struct lan78xx_net *dev = netdev_priv(netdev);
int ll_mtu = new_mtu + netdev->hard_header_len;
int old_hard_mtu = dev->hard_mtu;
int old_rx_urb_size = dev->rx_urb_size;
int max_frame_len = RX_MAX_FRAME_LEN(new_mtu);
int ret;

/* no second zero-length packet read wanted after mtu-sized packets */
if ((ll_mtu % dev->maxpacket) == 0)
if ((max_frame_len % dev->maxpacket) == 0)
return -EDOM;

ret = usb_autopm_get_interface(dev->intf);
if (ret < 0)
return ret;

lan78xx_set_rx_max_frame_length(dev, new_mtu + VLAN_ETH_HLEN);

netdev->mtu = new_mtu;

dev->hard_mtu = netdev->mtu + netdev->hard_header_len;
if (dev->rx_urb_size == old_hard_mtu) {
dev->rx_urb_size = dev->hard_mtu;
if (dev->rx_urb_size > old_rx_urb_size) {
if (netif_running(dev->net)) {
unlink_urbs(dev, &dev->rxq);
tasklet_schedule(&dev->bh);
}
}
}
ret = lan78xx_set_rx_max_frame_length(dev, max_frame_len);
if (!ret)
netdev->mtu = new_mtu;

usb_autopm_put_interface(dev->intf);

return 0;
return ret;
}

static int lan78xx_set_mac_addr(struct net_device *netdev, void *p)
Expand Down Expand Up @@ -3084,7 +3072,7 @@ static int lan78xx_reset(struct lan78xx_net *dev)
return ret;

ret = lan78xx_set_rx_max_frame_length(dev,
dev->net->mtu + VLAN_ETH_HLEN);
RX_MAX_FRAME_LEN(dev->net->mtu));

return ret;
}
Expand Down Expand Up @@ -3489,9 +3477,6 @@ static int lan78xx_bind(struct lan78xx_net *dev, struct usb_interface *intf)
goto out1;
}

dev->net->hard_header_len += TX_OVERHEAD;
dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;

/* Init all registers */
ret = lan78xx_reset(dev);
if (ret) {
Expand Down Expand Up @@ -3592,7 +3577,7 @@ static void lan78xx_skb_return(struct lan78xx_net *dev, struct sk_buff *skb)

static int lan78xx_rx(struct lan78xx_net *dev, struct sk_buff *skb)
{
if (skb->len < dev->net->hard_header_len)
if (skb->len < RX_SKB_MIN_LEN)
return 0;

while (skb->len > 0) {
Expand Down Expand Up @@ -3699,7 +3684,7 @@ static void rx_complete(struct urb *urb)

switch (urb_status) {
case 0:
if (skb->len < dev->net->hard_header_len) {
if (skb->len < RX_SKB_MIN_LEN) {
state = rx_cleanup;
dev->net->stats.rx_errors++;
dev->net->stats.rx_length_errors++;
Expand Down Expand Up @@ -4343,6 +4328,9 @@ static int lan78xx_probe(struct usb_interface *intf,
if (ret < 0)
goto out3;

/* MTU range: 68 - 9000 */
netdev->max_mtu = MAX_SINGLE_PACKET_SIZE;

netif_set_gso_max_size(netdev, LAN78XX_TSO_SIZE(dev));

tasklet_setup(&dev->bh, lan78xx_bh);
Expand Down Expand Up @@ -4390,13 +4378,6 @@ static int lan78xx_probe(struct usb_interface *intf,
if (ret < 0)
goto out4;

if (netdev->mtu > (dev->hard_mtu - netdev->hard_header_len))
netdev->mtu = dev->hard_mtu - netdev->hard_header_len;

/* MTU range: 68 - 9000 */
netdev->max_mtu = MAX_SINGLE_PACKET_SIZE;
netif_set_gso_max_size(netdev, MAX_SINGLE_PACKET_SIZE - MAX_HEADER);

period = ep_intr->desc.bInterval;
maxp = usb_maxpacket(dev->udev, dev->pipe_intr, 0);
buf = kmalloc(maxp, GFP_KERNEL);
Expand Down

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