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| author | Ben Hutchings <ben.hutchings@codethink.co.uk> | 2015-03-25 21:41:33 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-03-29 12:06:45 -0700 |
| commit | 7a1e890e2168e33fb62d84528e996b8b4b478fea (patch) | |
| tree | 2b9d47228b9d613a9934f8bddde26a6633cf748e /drivers/net/usb/cdc_ncm.c | |
| parent | 1e9e39f4a29857a396ac7b669d109f697f66695e (diff) | |
| download | lwn-7a1e890e2168e33fb62d84528e996b8b4b478fea.tar.gz lwn-7a1e890e2168e33fb62d84528e996b8b4b478fea.zip | |
usbnet: Fix tx_bytes statistic running backward in cdc_ncm
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@codethink.co.uk>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Diffstat (limited to 'drivers/net/usb/cdc_ncm.c')
| -rw-r--r-- | drivers/net/usb/cdc_ncm.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index 70cbea551139..c3e4da9e79ca 100644 --- 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, struct sk_buff *skb, __le32 sign) 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; |