[PATCH 1/2][KERNEL] usbnet: changes for upcoming cdc_ncm driver


tom.zanussi@...
 

From: Alexey Orishko

Changes:
include/linux/usb/usbnet.h:
- a new flag to indicate driver's capability to accumulate IP packets in Tx
direction and extract several packets from single skb in Rx direction.
drivers/net/usb/usbnet.c:
- the procedure of counting packets in usbnet was updated due to the
accumulating of IP packets in the driver
- no short packets are sent if indicated by the flag in driver_info
structure

commit 073285fd392f6dc901da7c698d46e1e2a7e26436 upstream

Signed-off-by: Alexey Orishko
Signed-off-by: David S. Miller
Integrated-by: Dongxiao Xu
---
drivers/net/usb/usbnet.c | 45 ++++++++++++++++++++++++++++++-------------
include/linux/usb/usbnet.h | 6 +++++
2 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index c04d49e..cff74b8 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -391,14 +391,19 @@ static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
goto error;
// else network stack removes extra byte if we forced a short packet

- if (skb->len)
- usbnet_skb_return (dev, skb);
- else {
- netif_dbg(dev, rx_err, dev->net, "drop\n");
-error:
- dev->net->stats.rx_errors++;
- skb_queue_tail (&dev->done, skb);
+ if (skb->len) {
+ /* all data was already cloned from skb inside the driver */
+ if (dev->driver_info->flags & FLAG_MULTI_PACKET)
+ dev_kfree_skb_any(skb);
+ else
+ usbnet_skb_return(dev, skb);
+ return;
}
+
+ netif_dbg(dev, rx_err, dev->net, "drop\n");
+error:
+ dev->net->stats.rx_errors++;
+ skb_queue_tail(&dev->done, skb);
}

/*-------------------------------------------------------------------------*/
@@ -971,7 +976,8 @@ static void tx_complete (struct urb *urb)
struct usbnet *dev = entry->dev;

if (urb->status == 0) {
- dev->net->stats.tx_packets++;
+ if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
+ dev->net->stats.tx_packets++;
dev->net->stats.tx_bytes += entry->length;
} else {
dev->net->stats.tx_errors++;
@@ -1044,8 +1050,13 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
if (info->tx_fixup) {
skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
if (!skb) {
- netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
- goto drop;
+ if (netif_msg_tx_err(dev)) {
+ netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
+ goto drop;
+ } else {
+ /* cdc_ncm collected packet; waits for more */
+ goto not_drop;
+ }
}
}
length = skb->len;
@@ -1067,13 +1078,18 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
/* don't assume the hardware handles USB_ZERO_PACKET
* NOTE: strictly conforming cdc-ether devices should expect
* the ZLP here, but ignore the one-byte packet.
+ * NOTE2: CDC NCM specification is different from CDC ECM when
+ * handling ZLP/short packets, so cdc_ncm driver will make short
+ * packet itself if needed.
*/
if (length % dev->maxpacket == 0) {
if (!(info->flags & FLAG_SEND_ZLP)) {
- urb->transfer_buffer_length++;
- if (skb_tailroom(skb)) {
- skb->data[skb->len] = 0;
- __skb_put(skb, 1);
+ if (!(info->flags & FLAG_MULTI_PACKET)) {
+ urb->transfer_buffer_length++;
+ if (skb_tailroom(skb)) {
+ skb->data[skb->len] = 0;
+ __skb_put(skb, 1);
+ }
}
} else
urb->transfer_flags |= URB_ZERO_PACKET;
@@ -1122,6 +1138,7 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
drop:
dev->net->stats.tx_dropped++;
+not_drop:
if (skb)
dev_kfree_skb_any (skb);
usb_free_urb (urb);
diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index 7ae27a4..44842c8 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -97,6 +97,12 @@ struct driver_info {

#define FLAG_LINK_INTR 0x0800 /* updates link (carrier) status */

+/*
+ * Indicates to usbnet, that USB driver accumulates multiple IP packets.
+ * Affects statistic (counters) and short packet handling.
+ */
+#define FLAG_MULTI_PACKET 0x1000
+
/* init device ... can sleep, or cause probe() failure */
int (*bind)(struct usbnet *, struct usb_interface *);

--
1.7.0.4

Join yocto@lists.yoctoproject.org to automatically receive all group messages.