forcedeth: fix stats on hardware without extended stats support

This change makes sure that tx_packets/rx_bytes ifconfig counters are
updated even on NICs that don't provide hardware support for these
stats: they are now updated in software. For the sake of consistency,
we also now have tx_bytes updated in software (hardware counters
include ethernet CRC, and software doesn't account for it).

This reverts parts of:
 - "forcedeth: statistics optimization" (21828163b2)
 - "forcedeth: Improve stats counters" (0bdfea8ba8)
 - "forcedeth: remove unneeded stats updates" (4687f3f364)

Tested:
  pktgen + loopback (http://patchwork.ozlabs.org/patch/124698/)
  reports identical tx_packets/rx_packets and tx_bytes/rx_bytes.

Signed-off-by: David Decotigny <david.decotigny@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 898bdf2cb43eb0a962c397eb4dd1aec2c7211be2)

diff --git a/drivers/net/ethernet/nvidia/forcedeth.c b/drivers/net/ethernet/nvidia/forcedeth.c
index 01bb7bfe14e6c9e25ef3614d390f63fff0241599..268ca169ae5a3663c8fdd90533cf3f58307ed7aa 100644 (file)
--- a/drivers/net/ethernet/nvidia/forcedeth.c
+++ b/drivers/net/ethernet/nvidia/forcedeth.c
@@ -609,7 +609,7 @@ struct nv_ethtool_str {
 };
 
 static const struct nv_ethtool_str nv_estats_str[] = {
-       { "tx_bytes" },
+       { "tx_bytes" }, /* includes Ethernet FCS CRC */
        { "tx_zero_rexmt" },
        { "tx_one_rexmt" },
        { "tx_many_rexmt" },
@@ -637,7 +637,7 @@ static const struct nv_ethtool_str nv_estats_str[] = {
        /* version 2 stats */
        { "tx_deferral" },
        { "tx_packets" },
-       { "rx_bytes" },
+       { "rx_bytes" }, /* includes Ethernet FCS CRC */
        { "tx_pause" },
        { "rx_pause" },
        { "rx_drop_frame" },
@@ -649,7 +649,7 @@ static const struct nv_ethtool_str nv_estats_str[] = {
 };
 
 struct nv_ethtool_stats {
-       u64 tx_bytes;
+       u64 tx_bytes; /* should be ifconfig->tx_bytes + 4*tx_packets */
        u64 tx_zero_rexmt;
        u64 tx_one_rexmt;
        u64 tx_many_rexmt;
@@ -670,14 +670,14 @@ struct nv_ethtool_stats {
        u64 rx_unicast;
        u64 rx_multicast;
        u64 rx_broadcast;
-       u64 rx_packets;
+       u64 rx_packets; /* should be ifconfig->rx_packets */
        u64 rx_errors_total;
        u64 tx_errors_total;
 
        /* version 2 stats */
        u64 tx_deferral;
-       u64 tx_packets;
-       u64 rx_bytes;
+       u64 tx_packets; /* should be ifconfig->tx_packets */
+       u64 rx_bytes;   /* should be ifconfig->rx_bytes + 4*rx_packets */
        u64 tx_pause;
        u64 rx_pause;
        u64 rx_drop_frame;
@@ -1706,10 +1706,17 @@ static struct net_device_stats *nv_get_stats(struct net_device *dev)
        if (np->driver_data & (DEV_HAS_STATISTICS_V1|DEV_HAS_STATISTICS_V2|DEV_HAS_STATISTICS_V3)) {
                nv_get_hw_stats(dev);
 
+               /*
+                * Note: because HW stats are not always available and
+                * for consistency reasons, the following ifconfig
+                * stats are managed by software: rx_bytes, tx_bytes,
+                * rx_packets and tx_packets. The related hardware
+                * stats reported by ethtool should be equivalent to
+                * these ifconfig stats, with 4 additional bytes per
+                * packet (Ethernet FCS CRC).
+                */
+
                /* copy to net_device stats */
-               dev->stats.tx_packets = np->estats.tx_packets;
-               dev->stats.rx_bytes = np->estats.rx_bytes;
-               dev->stats.tx_bytes = np->estats.tx_bytes;
                dev->stats.tx_fifo_errors = np->estats.tx_fifo_errors;
                dev->stats.tx_carrier_errors = np->estats.tx_carrier_errors;
                dev->stats.rx_crc_errors = np->estats.rx_crc_errors;
@@ -2380,6 +2387,9 @@ static int nv_tx_done(struct net_device *dev, int limit)
                                if (flags & NV_TX_ERROR) {
                                        if ((flags & NV_TX_RETRYERROR) && !(flags & NV_TX_RETRYCOUNT_MASK))
                                                nv_legacybackoff_reseed(dev);
+                               } else {
+                                       dev->stats.tx_packets++;
+                                       dev->stats.tx_bytes += np->get_tx_ctx->skb->len;
                                }
                                dev_kfree_skb_any(np->get_tx_ctx->skb);
                                np->get_tx_ctx->skb = NULL;
@@ -2390,6 +2400,9 @@ static int nv_tx_done(struct net_device *dev, int limit)
                                if (flags & NV_TX2_ERROR) {
                                        if ((flags & NV_TX2_RETRYERROR) && !(flags & NV_TX2_RETRYCOUNT_MASK))
                                                nv_legacybackoff_reseed(dev);
+                               } else {
+                                       dev->stats.tx_packets++;
+                                       dev->stats.tx_bytes += np->get_tx_ctx->skb->len;
                                }
                                dev_kfree_skb_any(np->get_tx_ctx->skb);
                                np->get_tx_ctx->skb = NULL;
@@ -2429,6 +2442,9 @@ static int nv_tx_done_optimized(struct net_device *dev, int limit)
                                        else
                                                nv_legacybackoff_reseed(dev);
                                }
+                       } else {
+                               dev->stats.tx_packets++;
+                               dev->stats.tx_bytes += np->get_tx_ctx->skb->len;
                        }
 
                        dev_kfree_skb_any(np->get_tx_ctx->skb);
@@ -2678,6 +2694,7 @@ static int nv_rx_process(struct net_device *dev, int limit)
                skb->protocol = eth_type_trans(skb, dev);
                napi_gro_receive(&np->napi, skb);
                dev->stats.rx_packets++;
+               dev->stats.rx_bytes += len;
 next_pkt:
                if (unlikely(np->get_rx.orig++ == np->last_rx.orig))
                        np->get_rx.orig = np->first_rx.orig;
@@ -2761,6 +2778,7 @@ static int nv_rx_process_optimized(struct net_device *dev, int limit)
                        }
                        napi_gro_receive(&np->napi, skb);
                        dev->stats.rx_packets++;
+                       dev->stats.rx_bytes += len;
                } else {
                        dev_kfree_skb(skb);
                }