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path: root/drivers/net/can/usb/kvaser_usb.c
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Diffstat (limited to 'drivers/net/can/usb/kvaser_usb.c')
-rw-r--r--drivers/net/can/usb/kvaser_usb.c48
1 files changed, 31 insertions, 17 deletions
diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c
index 2928f7003041..a316fa4b91ab 100644
--- a/drivers/net/can/usb/kvaser_usb.c
+++ b/drivers/net/can/usb/kvaser_usb.c
@@ -14,6 +14,7 @@
* Copyright (C) 2015 Valeo S.A.
*/
+#include <linux/kernel.h>
#include <linux/completion.h>
#include <linux/module.h>
#include <linux/netdevice.h>
@@ -584,8 +585,15 @@ static int kvaser_usb_wait_msg(const struct kvaser_usb *dev, u8 id,
while (pos <= actual_len - MSG_HEADER_LEN) {
tmp = buf + pos;
- if (!tmp->len)
- break;
+ /* Handle messages crossing the USB endpoint max packet
+ * size boundary. Check kvaser_usb_read_bulk_callback()
+ * for further details.
+ */
+ if (tmp->len == 0) {
+ pos = round_up(pos,
+ dev->bulk_in->wMaxPacketSize);
+ continue;
+ }
if (pos + tmp->len > actual_len) {
dev_err(dev->udev->dev.parent,
@@ -787,7 +795,6 @@ static int kvaser_usb_simple_msg_async(struct kvaser_usb_net_priv *priv,
netdev_err(netdev, "Error transmitting URB\n");
usb_unanchor_urb(urb);
usb_free_urb(urb);
- kfree(buf);
return err;
}
@@ -1317,8 +1324,19 @@ static void kvaser_usb_read_bulk_callback(struct urb *urb)
while (pos <= urb->actual_length - MSG_HEADER_LEN) {
msg = urb->transfer_buffer + pos;
- if (!msg->len)
- break;
+ /* The Kvaser firmware can only read and write messages that
+ * does not cross the USB's endpoint wMaxPacketSize boundary.
+ * If a follow-up command crosses such boundary, firmware puts
+ * a placeholder zero-length command in its place then aligns
+ * the real command to the next max packet size.
+ *
+ * Handle such cases or we're going to miss a significant
+ * number of events in case of a heavy rx load on the bus.
+ */
+ if (msg->len == 0) {
+ pos = round_up(pos, dev->bulk_in->wMaxPacketSize);
+ continue;
+ }
if (pos + msg->len > urb->actual_length) {
dev_err(dev->udev->dev.parent, "Format error\n");
@@ -1326,7 +1344,6 @@ static void kvaser_usb_read_bulk_callback(struct urb *urb)
}
kvaser_usb_handle_message(dev, msg);
-
pos += msg->len;
}
@@ -1615,8 +1632,7 @@ static netdev_tx_t kvaser_usb_start_xmit(struct sk_buff *skb,
struct urb *urb;
void *buf;
struct kvaser_msg *msg;
- int i, err;
- int ret = NETDEV_TX_OK;
+ int i, err, ret = NETDEV_TX_OK;
u8 *msg_tx_can_flags = NULL; /* GCC */
if (can_dropped_invalid_skb(netdev, skb))
@@ -1634,7 +1650,7 @@ static netdev_tx_t kvaser_usb_start_xmit(struct sk_buff *skb,
if (!buf) {
stats->tx_dropped++;
dev_kfree_skb(skb);
- goto nobufmem;
+ goto freeurb;
}
msg = buf;
@@ -1681,8 +1697,10 @@ static netdev_tx_t kvaser_usb_start_xmit(struct sk_buff *skb,
/* This should never happen; it implies a flow control bug */
if (!context) {
netdev_warn(netdev, "cannot find free context\n");
+
+ kfree(buf);
ret = NETDEV_TX_BUSY;
- goto releasebuf;
+ goto freeurb;
}
context->priv = priv;
@@ -1719,16 +1737,12 @@ static netdev_tx_t kvaser_usb_start_xmit(struct sk_buff *skb,
else
netdev_warn(netdev, "Failed tx_urb %d\n", err);
- goto releasebuf;
+ goto freeurb;
}
- usb_free_urb(urb);
-
- return NETDEV_TX_OK;
+ ret = NETDEV_TX_OK;
-releasebuf:
- kfree(buf);
-nobufmem:
+freeurb:
usb_free_urb(urb);
return ret;
}