netdev - [PATCH v2 3/4] USBNET: support DMA SG

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1375692423-9497-4-git-send-email-ming.lei@canonical.com>
Date:	Mon,  5 Aug 2013 16:47:02 +0800
From:	Ming Lei <ming.lei@...onical.com>
To:	"David S. Miller" <davem@...emloft.net>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Oliver Neukum <oneukum@...e.de>,
	Sarah Sharp <sarah.a.sharp@...ux.intel.com>,
	netdev@...r.kernel.org, linux-usb@...r.kernel.org,
	Ming Lei <ming.lei@...onical.com>,
	Eric Dumazet <eric.dumazet@...il.com>,
	Ben Hutchings <bhutchings@...arflare.com>,
	Grant Grundler <grundler@...gle.com>,
	Freddy Xin <freddy@...x.com.tw>,
	Alan Stern <stern@...land.harvard.edu>
Subject: [PATCH v2 3/4] 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: Eric Dumazet <eric.dumazet@...il.com>
Cc: Ben Hutchings <bhutchings@...arflare.com>
Cc: Grant Grundler <grundler@...gle.com>
Cc: Freddy Xin <freddy@...x.com.tw>
Cc: Oliver Neukum <oneukum@...e.de>
Cc: Alan Stern <stern@...land.harvard.edu>
Signed-off-by: Ming Lei <ming.lei@...onical.com>
---
 drivers/net/usb/usbnet.c   |   39 +++++++++++++++++++++++++++++++++++++--
 include/linux/usb/usbnet.h |    1 +
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index e4811d7..615d78e 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1232,6 +1232,37 @@ 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)
 {
@@ -1258,7 +1289,6 @@ 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");
@@ -1268,10 +1298,14 @@ 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
@@ -1391,6 +1425,7 @@ 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);
diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index 8fbc008..9cb2fe8 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -35,6 +35,7 @@ struct usbnet {
 	unsigned char		suspend_count;
 	unsigned char		pkt_cnt, pkt_err;
 	unsigned short		rx_qlen, tx_qlen;
+	unsigned		can_dma_sg:1;
 
 	/* i/o info: pipes etc */
 	unsigned		in, out;
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html