From 638c5115a794981441246fa8fa5d95c1875af5ba Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 8 Aug 2013 21:48:24 +0800 Subject: USBNET: support DMA SG This patch introduces support of DMA SG if the USB host controller which usbnet device is attached to is capable of building packet from discontinuous buffers. The patch supports passing the skb fragment buffers to usb stack directly via urb->sg. Cc: Ben Hutchings Cc: Grant Grundler Cc: Freddy Xin Cc: Alan Stern Acked-by: Oliver Neukum Signed-off-by: Ming Lei Reviewed-by: Eric Dumazet Acked-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/usbnet.c | 45 ++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 42 insertions(+), 3 deletions(-) (limited to 'drivers/net/usb') diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index 06ee82f557d4..27a00b006033 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -1197,6 +1197,37 @@ EXPORT_SYMBOL_GPL(usbnet_tx_timeout); /*-------------------------------------------------------------------------*/ +static int build_dma_sg(const struct sk_buff *skb, struct urb *urb) +{ + unsigned num_sgs, total_len = 0; + int i, s = 0; + + num_sgs = skb_shinfo(skb)->nr_frags + 1; + if (num_sgs == 1) + return 0; + + urb->sg = kmalloc(num_sgs * sizeof(struct scatterlist), GFP_ATOMIC); + if (!urb->sg) + return -ENOMEM; + + urb->num_sgs = num_sgs; + sg_init_table(urb->sg, urb->num_sgs); + + sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb)); + total_len += skb_headlen(skb); + + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + struct skb_frag_struct *f = &skb_shinfo(skb)->frags[i]; + + total_len += skb_frag_size(f); + sg_set_page(&urb->sg[i + s], f->page.p, f->size, + f->page_offset); + } + urb->transfer_buffer_length = total_len; + + return 1; +} + netdev_tx_t usbnet_start_xmit (struct sk_buff *skb, struct net_device *net) { @@ -1223,7 +1254,6 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb, goto drop; } } - length = skb->len; if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) { netif_dbg(dev, tx_err, dev->net, "no urb\n"); @@ -1233,10 +1263,14 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb, entry = (struct skb_data *) skb->cb; entry->urb = urb; entry->dev = dev; - entry->length = length; usb_fill_bulk_urb (urb, dev->udev, dev->out, skb->data, skb->len, tx_complete, skb); + if (dev->can_dma_sg) { + if (build_dma_sg(skb, urb) < 0) + goto drop; + } + entry->length = length = urb->transfer_buffer_length; /* don't assume the hardware handles USB_ZERO_PACKET * NOTE: strictly conforming cdc-ether devices should expect @@ -1305,7 +1339,10 @@ drop: not_drop: if (skb) dev_kfree_skb_any (skb); - usb_free_urb (urb); + if (urb) { + kfree(urb->sg); + usb_free_urb(urb); + } } else netif_dbg(dev, tx_queued, dev->net, "> tx, len %d, type 0x%x\n", length, skb->protocol); @@ -1356,6 +1393,7 @@ static void usbnet_bh (unsigned long param) rx_process (dev, skb); continue; case tx_done: + kfree(entry->urb->sg); case rx_cleanup: usb_free_urb (entry->urb); dev_kfree_skb (skb); @@ -1689,6 +1727,7 @@ int usbnet_resume (struct usb_interface *intf) retval = usb_submit_urb(res, GFP_ATOMIC); if (retval < 0) { dev_kfree_skb_any(skb); + kfree(res->sg); usb_free_urb(res); usb_autopm_put_interface_async(dev->intf); } else { -- cgit v1.2.3 From 3804fad45411b48233b48003e33a78f290d227c8 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 8 Aug 2013 21:48:25 +0800 Subject: USBNET: ax88179_178a: enable tso if usb host supports sg dma This patch enables 'can_dma_sg' flag for ax88179_178a device if the attached host controller supports building packet from discontinuous buffers(DMA SG is possible), so TSO can be enabled and skb fragment buffers can be passed to usb stack via urb->sg directly. With the patch, system CPU utilization decreased ~50% and throughput increased by ~10% when doing iperf client test on one ARM A15 dual core board. Cc: Ben Hutchings Cc: Grant Grundler Cc: Oliver Neukum Cc: Alan Stern Cc: Freddy Xin Signed-off-by: Ming Lei Acked-by: Eric Dumazet Acked-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/ax88179_178a.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/net/usb') diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c index 2bc87e3a8141..4233c05a3e32 100644 --- a/drivers/net/usb/ax88179_178a.c +++ b/drivers/net/usb/ax88179_178a.c @@ -1028,12 +1028,20 @@ static int ax88179_bind(struct usbnet *dev, struct usb_interface *intf) dev->mii.phy_id = 0x03; dev->mii.supports_gmii = 1; + if (usb_device_no_sg_constraint(dev->udev)) + dev->can_dma_sg = 1; + dev->net->features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM | NETIF_F_RXCSUM; dev->net->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM | NETIF_F_RXCSUM; + if (dev->can_dma_sg) { + dev->net->features |= NETIF_F_SG | NETIF_F_TSO; + dev->net->hw_features |= NETIF_F_SG | NETIF_F_TSO; + } + /* Enable checksum offload */ *tmp = AX_RXCOE_IP | AX_RXCOE_TCP | AX_RXCOE_UDP | AX_RXCOE_TCPV6 | AX_RXCOE_UDPV6; -- cgit v1.2.3