[PATCH net-next v2 1/3] net: qualcomm: rmnet: Capture all drops in transmit path

[Subash Abhinov Kasiviswanathan]

Packets in transmit path could potentially be dropped if there were
errors while adding the MAP header or the checksum header.
Increment the tx_drops stats in these cases.

Additionally, refactor the code to free the packet and increment
the tx_drops stat under a single label.

Signed-off-by: Subash Abhinov Kasiviswanathan <subas...@codeaurora.org>
---
 .../net/ethernet/qualcomm/rmnet/rmnet_handlers.c    | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c 
b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index 6fcd586..7fd86d4 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
@@ -148,7 +148,7 @@ static int rmnet_map_egress_handler(struct sk_buff *skb,
 
        if (skb_headroom(skb) < required_headroom) {
                if (pskb_expand_head(skb, required_headroom, 0, GFP_KERNEL))
-                       goto fail;
+                       return -ENOMEM;
        }
 
        if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4)
@@ -156,17 +156,13 @@ static int rmnet_map_egress_handler(struct sk_buff *skb,
 
        map_header = rmnet_map_add_map_header(skb, additional_header_len, 0);
        if (!map_header)
-               goto fail;
+               return -ENOMEM;
 
        map_header->mux_id = mux_id;
 
        skb->protocol = htons(ETH_P_MAP);
 
        return 0;
-
-fail:
-       kfree_skb(skb);
-       return -ENOMEM;
 }
 
 static void
@@ -228,15 +224,18 @@ void rmnet_egress_handler(struct sk_buff *skb)
        mux_id = priv->mux_id;
 
        port = rmnet_get_port(skb->dev);
-       if (!port) {
-               kfree_skb(skb);
-               return;
-       }
+       if (!port)
+               goto drop;
 
        if (rmnet_map_egress_handler(skb, port, mux_id, orig_dev))
-               return;
+               goto drop;
 
        rmnet_vnd_tx_fixup(skb, orig_dev);
 
        dev_queue_xmit(skb);
+       return;
+
+drop:
+       this_cpu_inc(priv->pcpu_stats->stats.tx_drops);
+       kfree_skb(skb);
 }
-- 
1.9.1