[PATCH net-next 3/3] veth: Add ethtool statistics support for XDP

[Toshiaki Makita]

Expose per-queue stats for ethtool -S.
As there are only rx queues, and rx queues are used only when XDP is
used, per-queue counters are only rx XDP ones.

Example:

$ ethtool -S veth0
NIC statistics:
     peer_ifindex: 11
     rx_queue_0_xdp_packets: 28601434
     rx_queue_0_xdp_bytes: 1716086040
     rx_queue_0_xdp_drops: 28601434
     rx_queue_1_xdp_packets: 17873050
     rx_queue_1_xdp_bytes: 1072383000
     rx_queue_1_xdp_drops: 17873050

Signed-off-by: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp>
---
 drivers/net/veth.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 46 insertions(+), 2 deletions(-)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 68bb93d..890fa5b 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -67,6 +67,21 @@ struct veth_priv {
  * ethtool interface
  */
 
+struct veth_q_stat_desc {
+       char    desc[ETH_GSTRING_LEN];
+       size_t  offset;
+};
+
+#define VETH_RQ_STAT(m)        offsetof(struct veth_rq_stats, m)
+
+static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
+       { "xdp_packets",        VETH_RQ_STAT(xdp_packets) },
+       { "xdp_bytes",          VETH_RQ_STAT(xdp_bytes) },
+       { "xdp_drops",          VETH_RQ_STAT(xdp_drops) },
+};
+
+#define VETH_RQ_STATS_LEN      ARRAY_SIZE(veth_rq_stats_desc)
+
 static struct {
        const char string[ETH_GSTRING_LEN];
 } ethtool_stats_keys[] = {
@@ -91,9 +106,20 @@ static void veth_get_drvinfo(struct net_device *dev, struct 
ethtool_drvinfo *inf
 
 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
 {
+       char *p = (char *)buf;
+       int i, j;
+
        switch(stringset) {
        case ETH_SS_STATS:
-               memcpy(buf, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
+               memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
+               p += sizeof(ethtool_stats_keys);
+               for (i = 0; i < dev->real_num_rx_queues; i++) {
+                       for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
+                               snprintf(p, ETH_GSTRING_LEN, "rx_queue_%u_%s",
+                                        i, veth_rq_stats_desc[j].desc);
+                               p += ETH_GSTRING_LEN;
+                       }
+               }
                break;
        }
 }
@@ -102,7 +128,8 @@ static int veth_get_sset_count(struct net_device *dev, int 
sset)
 {
        switch (sset) {
        case ETH_SS_STATS:
-               return ARRAY_SIZE(ethtool_stats_keys);
+               return ARRAY_SIZE(ethtool_stats_keys) +
+                      VETH_RQ_STATS_LEN * dev->real_num_rx_queues;
        default:
                return -EOPNOTSUPP;
        }
@@ -113,8 +140,25 @@ static void veth_get_ethtool_stats(struct net_device *dev,
 {
        struct veth_priv *priv = netdev_priv(dev);
        struct net_device *peer = rtnl_dereference(priv->peer);
+       int i, j, idx;
 
        data[0] = peer ? peer->ifindex : 0;
+       idx = 1;
+       for (i = 0; i < dev->real_num_rx_queues; i++) {
+               const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
+               const void *stats_base = (void *)rq_stats;
+               unsigned int start;
+               size_t offset;
+
+               do {
+                       start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
+                       for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
+                               offset = veth_rq_stats_desc[j].offset;
+                               data[idx + j] = *(u64 *)(stats_base + offset);
+                       }
+               } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
+               idx += VETH_RQ_STATS_LEN;
+       }
 }
 
 static int veth_get_ts_info(struct net_device *dev,
-- 
1.8.3.1