hv_netvsc: add ethtool statistics for tx packet issues

Printing console messages is not helpful when system is out of memory;
and can be disastrous with netconsole. Instead keep statistics
of these anomalous conditions.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 8031dee..284b97b 100644 (file)
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -652,6 +652,14 @@ struct netvsc_stats {
        struct u64_stats_sync syncp;
 };
 
+struct netvsc_ethtool_stats {
+       unsigned long tx_scattered;
+       unsigned long tx_no_memory;
+       unsigned long tx_no_space;
+       unsigned long tx_too_big;
+       unsigned long tx_busy;
+};
+
 struct netvsc_reconfig {
        struct list_head list;
        u32 event;
@@ -681,6 +689,7 @@ struct net_device_context {
        /* Ethtool settings */
        u8 duplex;
        u32 speed;
+       struct netvsc_ethtool_stats eth_stats;
 
        /* the device is going away */
        bool start_remove;

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index b874ab1..2360e70 100644 (file)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -365,7 +365,6 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
        u32 skb_length;
        struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT];
        struct hv_page_buffer *pb = page_buf;
-       struct netvsc_stats *tx_stats = this_cpu_ptr(net_device_ctx->tx_stats);
 
        /* We will atmost need two pages to describe the rndis
         * header. We can only transmit MAX_PAGE_BUFFER_COUNT number
@@ -377,17 +376,14 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
        num_data_pgs = netvsc_get_slots(skb) + 2;
 
        if (unlikely(num_data_pgs > MAX_PAGE_BUFFER_COUNT)) {
-               if (skb_linearize(skb)) {
-                       net_alert_ratelimited("failed to linearize skb\n");
-                       ret = -ENOMEM;
-                       goto drop;
-               }
+               ++net_device_ctx->eth_stats.tx_scattered;
+
+               if (skb_linearize(skb))
+                       goto no_memory;
 
                num_data_pgs = netvsc_get_slots(skb) + 2;
                if (num_data_pgs > MAX_PAGE_BUFFER_COUNT) {
-                       net_alert_ratelimited("packet too big: %u pages (%u bytes)\n",
-                                             num_data_pgs, skb->len);
-                       ret = -EFAULT;
+                       ++net_device_ctx->eth_stats.tx_too_big;
                        goto drop;
                }
        }
@@ -398,11 +394,9 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
         * structure.
         */
        ret = skb_cow_head(skb, RNDIS_AND_PPI_SIZE);
-       if (ret) {
-               netdev_err(net, "unable to alloc hv_netvsc_packet\n");
-               ret = -ENOMEM;
-               goto drop;
-       }
+       if (ret)
+               goto no_memory;
+
        /* Use the skb control buffer for building up the packet */
        BUILD_BUG_ON(sizeof(struct hv_netvsc_packet) >
                        FIELD_SIZEOF(struct sk_buff, cb));
@@ -518,7 +512,7 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 
                ret = skb_cow_head(skb, 0);
                if (ret)
-                       goto drop;
+                       goto no_memory;
 
                uh = udp_hdr(skb);
                udp_len = ntohs(uh->len);
@@ -545,20 +539,32 @@ do_send:
        ret = netvsc_send(net_device_ctx->device_ctx, packet,
                          rndis_msg, &pb, skb);
        if (likely(ret == 0)) {
+               struct netvsc_stats *tx_stats = this_cpu_ptr(net_device_ctx->tx_stats);
+
                u64_stats_update_begin(&tx_stats->syncp);
                tx_stats->packets++;
                tx_stats->bytes += skb_length;
                u64_stats_update_end(&tx_stats->syncp);
                return NETDEV_TX_OK;
        }
-       if (ret == -EAGAIN)
+
+       if (ret == -EAGAIN) {
+               ++net_device_ctx->eth_stats.tx_busy;
                return NETDEV_TX_BUSY;
+       }
+
+       if (ret == -ENOSPC)
+               ++net_device_ctx->eth_stats.tx_no_space;
 
 drop:
        dev_kfree_skb_any(skb);
        net->stats.tx_dropped++;
 
        return NETDEV_TX_OK;
+
+no_memory:
+       ++net_device_ctx->eth_stats.tx_no_memory;
+       goto drop;
 }
 
 /*
@@ -1015,6 +1021,51 @@ static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
        return err;
 }
 
+static const struct {
+       char name[ETH_GSTRING_LEN];
+       u16 offset;
+} netvsc_stats[] = {
+       { "tx_scattered", offsetof(struct netvsc_ethtool_stats, tx_scattered) },
+       { "tx_no_memory",  offsetof(struct netvsc_ethtool_stats, tx_no_memory) },
+       { "tx_no_space",  offsetof(struct netvsc_ethtool_stats, tx_no_space) },
+       { "tx_too_big",   offsetof(struct netvsc_ethtool_stats, tx_too_big) },
+       { "tx_busy",      offsetof(struct netvsc_ethtool_stats, tx_busy) },
+};
+
+static int netvsc_get_sset_count(struct net_device *dev, int string_set)
+{
+       switch (string_set) {
+       case ETH_SS_STATS:
+               return ARRAY_SIZE(netvsc_stats);
+       default:
+               return -EINVAL;
+       }
+}
+
+static void netvsc_get_ethtool_stats(struct net_device *dev,
+                                    struct ethtool_stats *stats, u64 *data)
+{
+       struct net_device_context *ndc = netdev_priv(dev);
+       const void *nds = &ndc->eth_stats;
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(netvsc_stats); i++)
+               data[i] = *(unsigned long *)(nds + netvsc_stats[i].offset);
+}
+
+static void netvsc_get_strings(struct net_device *dev, u32 stringset, u8 *data)
+{
+       int i;
+
+       switch (stringset) {
+       case ETH_SS_STATS:
+               for (i = 0; i < ARRAY_SIZE(netvsc_stats); i++)
+                       memcpy(data + i * ETH_GSTRING_LEN,
+                              netvsc_stats[i].name, ETH_GSTRING_LEN);
+               break;
+       }
+}
+
 #ifdef CONFIG_NET_POLL_CONTROLLER
 static void netvsc_poll_controller(struct net_device *net)
 {
@@ -1027,6 +1078,9 @@ static void netvsc_poll_controller(struct net_device *net)
 static const struct ethtool_ops ethtool_ops = {
        .get_drvinfo    = netvsc_get_drvinfo,
        .get_link       = ethtool_op_get_link,
+       .get_ethtool_stats = netvsc_get_ethtool_stats,
+       .get_sset_count = netvsc_get_sset_count,
+       .get_strings    = netvsc_get_strings,
        .get_channels   = netvsc_get_channels,
        .set_channels   = netvsc_set_channels,
        .get_ts_info    = ethtool_op_get_ts_info,