macvlan: lockless tx path

macvlan is a stacked device, like tunnels. We should use the lockless
mechanism we are using in tunnels and loopback.

This patch completely removes locking in TX path.

tx stat counters are added into existing percpu stat structure, renamed
from rx_stats to pcpu_stats.

Note : this reverts commit 2c11455321f37 (macvlan: add multiqueue
capability)

Note : rx_errors converted to a 32bit counter, like tx_dropped, since
they dont need 64bit range.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Ben Greear <greearb@candelatech.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 14 deletions

diff --git a/include/linux/if_macvlan.h b/include/linux/if_macvlan.h
index ac96a2d76291..e28b2e4959d4 100644
--- a/include/linux/if_macvlan.h
+++ b/include/linux/if_macvlan.h
@@ -25,19 +25,25 @@ struct macvlan_port;
 struct macvtap_queue;
 
 /**
- *      struct macvlan_rx_stats - MACVLAN percpu rx stats
+ *      struct macvlan_pcpu_stats - MACVLAN percpu stats
  *      @rx_packets: number of received packets
  *      @rx_bytes: number of received bytes
  *      @rx_multicast: number of received multicast packets
+ *      @tx_packets: number of transmitted packets
+ *      @tx_bytes: number of transmitted bytes
  *      @syncp: synchronization point for 64bit counters
- *      @rx_errors: number of errors
+ *      @rx_errors: number of rx errors
+ *      @tx_dropped: number of tx dropped packets
  */
-struct macvlan_rx_stats {
+struct macvlan_pcpu_stats {
         u64                     rx_packets;
         u64                     rx_bytes;
         u64                     rx_multicast;
+        u64                     tx_packets;
+        u64                     tx_bytes;
         struct u64_stats_sync   syncp;
-        unsigned long           rx_errors;
+        u32                     rx_errors;
+        u32                     tx_dropped;
 };
 
 /*
@@ -52,7 +58,7 @@ struct macvlan_dev {
         struct hlist_node       hlist;
         struct macvlan_port     *port;
         struct net_device       *lowerdev;
-        struct macvlan_rx_stats __percpu *rx_stats;
+        struct macvlan_pcpu_stats __percpu *pcpu_stats;
         enum macvlan_mode       mode;
         int (*receive)(struct sk_buff *skb);
         int (*forward)(struct net_device *dev, struct sk_buff *skb);
@@ -64,18 +70,18 @@ static inline void macvlan_count_rx(const struct macvlan_dev *vlan,
                                     unsigned int len, bool success,
                                     bool multicast)
 {
-        struct macvlan_rx_stats *rx_stats;
-
-        rx_stats = this_cpu_ptr(vlan->rx_stats);
         if (likely(success)) {
-                u64_stats_update_begin(&rx_stats->syncp);
-                rx_stats->rx_packets++;
-                rx_stats->rx_bytes += len;
+                struct macvlan_pcpu_stats *pcpu_stats;
+
+                pcpu_stats = this_cpu_ptr(vlan->pcpu_stats);
+                u64_stats_update_begin(&pcpu_stats->syncp);
+                pcpu_stats->rx_packets++;
+                pcpu_stats->rx_bytes += len;
                 if (multicast)
-                        rx_stats->rx_multicast++;
-                u64_stats_update_end(&rx_stats->syncp);
+                        pcpu_stats->rx_multicast++;
+                u64_stats_update_end(&pcpu_stats->syncp);
         } else {
-                rx_stats->rx_errors++;
+                this_cpu_inc(vlan->pcpu_stats->rx_errors);
         }
 }