This is a note to let you know that I've just added the patch titled
usbnet: Fix tx_bytes statistic running backward in cdc_ncm
to the 3.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usbnet-fix-tx_bytes-statistic-running-backward-in-cdc_ncm.patch
and it can be found in the queue-3.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Apr 21 23:05:14 CEST 2015
From: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Date: Wed, 25 Mar 2015 21:41:33 +0100
Subject: usbnet: Fix tx_bytes statistic running backward in cdc_ncm
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
[ Upstream commit 7a1e890e2168e33fb62d84528e996b8b4b478fea ]
cdc_ncm disagrees with usbnet about how much framing overhead should
be counted in the tx_bytes statistics, and tries 'fix' this by
decrementing tx_bytes on the transmit path. But statistics must never
be decremented except due to roll-over; this will thoroughly confuse
user-space. Also, tx_bytes is only incremented by usbnet in the
completion path.
Fix this by requiring drivers that set FLAG_MULTI_FRAME to set a
tx_bytes delta along with the tx_packets count.
Fixes: beeecd42c3b4 ("net: cdc_ncm/cdc_mbim: adding NCM protocol statistics")
Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Signed-off-by: Bjørn Mork <bjorn@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/usb/asix_common.c | 2 +-
drivers/net/usb/cdc_ncm.c | 7 +++----
drivers/net/usb/sr9800.c | 2 +-
drivers/net/usb/usbnet.c | 16 +++++++++++++---
include/linux/usb/usbnet.h | 6 ++++--
5 files changed, 22 insertions(+), 11 deletions(-)
--- a/drivers/net/usb/asix_common.c
+++ b/drivers/net/usb/asix_common.c
@@ -189,7 +189,7 @@ struct sk_buff *asix_tx_fixup(struct usb
skb_put(skb, sizeof(padbytes));
}
- usbnet_set_skb_tx_stats(skb, 1);
+ usbnet_set_skb_tx_stats(skb, 1, 0);
return skb;
}
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -1177,13 +1177,12 @@ cdc_ncm_fill_tx_frame(struct usbnet *dev
ctx->tx_overhead += skb_out->len - ctx->tx_curr_frame_payload;
ctx->tx_ntbs++;
- /* usbnet has already counted all the framing overhead.
+ /* usbnet will count all the framing overhead by default.
* Adjust the stats so that the tx_bytes counter show real
* payload data instead.
*/
- dev->net->stats.tx_bytes -= skb_out->len - ctx->tx_curr_frame_payload;
-
- usbnet_set_skb_tx_stats(skb_out, n);
+ usbnet_set_skb_tx_stats(skb_out, n,
+ ctx->tx_curr_frame_payload - skb_out->len);
return skb_out;
--- a/drivers/net/usb/sr9800.c
+++ b/drivers/net/usb/sr9800.c
@@ -144,7 +144,7 @@ static struct sk_buff *sr_tx_fixup(struc
skb_put(skb, sizeof(padbytes));
}
- usbnet_set_skb_tx_stats(skb, 1);
+ usbnet_set_skb_tx_stats(skb, 1, 0);
return skb;
}
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1347,9 +1347,19 @@ netdev_tx_t usbnet_start_xmit (struct sk
} else
urb->transfer_flags |= URB_ZERO_PACKET;
}
- entry->length = urb->transfer_buffer_length = length;
- if (!(info->flags & FLAG_MULTI_PACKET))
- usbnet_set_skb_tx_stats(skb, 1);
+ urb->transfer_buffer_length = length;
+
+ if (info->flags & FLAG_MULTI_PACKET) {
+ /* Driver has set number of packets and a length delta.
+ * Calculate the complete length and ensure that it's
+ * positive.
+ */
+ entry->length += length;
+ if (WARN_ON_ONCE(entry->length <= 0))
+ entry->length = length;
+ } else {
+ usbnet_set_skb_tx_stats(skb, 1, length);
+ }
spin_lock_irqsave(&dev->txq.lock, flags);
retval = usb_autopm_get_interface_async(dev->intf);
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -227,7 +227,7 @@ struct skb_data { /* skb->cb is one of t
struct urb *urb;
struct usbnet *dev;
enum skb_state state;
- size_t length;
+ long length;
unsigned long packets;
};
@@ -235,11 +235,13 @@ struct skb_data { /* skb->cb is one of t
* tx_fixup method before returning an skb.
*/
static inline void
-usbnet_set_skb_tx_stats(struct sk_buff *skb, unsigned long packets)
+usbnet_set_skb_tx_stats(struct sk_buff *skb,
+ unsigned long packets, long bytes_delta)
{
struct skb_data *entry = (struct skb_data *) skb->cb;
entry->packets = packets;
+ entry->length = bytes_delta;
}
extern int usbnet_open(struct net_device *net);
Patches currently in stable-queue which might be from ben.hutchings@xxxxxxxxxxxxxxx are
queue-3.19/usbnet-fix-tx_packets-stat-for-flag_multi_frame-drivers.patch
queue-3.19/usbnet-fix-tx_bytes-statistic-running-backward-in-cdc_ncm.patch
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