drivers/net/wan/hdlc_fr: Improvements to the code of pvc_xmit

1. Keep the code for the normal (non-error) flow at the lowest
indentation level. And use "goto drop" for all error handling.

2. Replace code that pads short Ethernet frames with a "__skb_pad" call.

3. Change "dev_kfree_skb" to "kfree_skb" in error handling code.
"kfree_skb" is the correct function to call when dropping an skb due to
an error. "dev_kfree_skb", which is an alias of "consume_skb", is for
dropping skbs normally (not due to an error).

Cc: Krzysztof Halasa <khc@pm.waw.pl>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c
index 3a44dad..4dfdbca 100644 (file)
--- a/drivers/net/wan/hdlc_fr.c
+++ b/drivers/net/wan/hdlc_fr.c
@@ -416,38 +416,36 @@ static netdev_tx_t pvc_xmit(struct sk_buff *skb, struct net_device *dev)
 {
        struct pvc_device *pvc = dev->ml_priv;
 
-       if (pvc->state.active) {
-               if (dev->type == ARPHRD_ETHER) {
-                       int pad = ETH_ZLEN - skb->len;
-                       if (pad > 0) { /* Pad the frame with zeros */
-                               int len = skb->len;
-                               if (skb_tailroom(skb) < pad)
-                                       if (pskb_expand_head(skb, 0, pad,
-                                                            GFP_ATOMIC)) {
-                                               dev->stats.tx_dropped++;
-                                               dev_kfree_skb(skb);
-                                               return NETDEV_TX_OK;
-                                       }
-                               skb_put(skb, pad);
-                               memset(skb->data + len, 0, pad);
-                       }
-               }
-               skb->dev = dev;
-               if (!fr_hard_header(&skb, pvc->dlci)) {
-                       dev->stats.tx_bytes += skb->len;
-                       dev->stats.tx_packets++;
-                       if (pvc->state.fecn) /* TX Congestion counter */
-                               dev->stats.tx_compressed++;
-                       skb->dev = pvc->frad;
-                       skb->protocol = htons(ETH_P_HDLC);
-                       skb_reset_network_header(skb);
-                       dev_queue_xmit(skb);
-                       return NETDEV_TX_OK;
+       if (!pvc->state.active)
+               goto drop;
+
+       if (dev->type == ARPHRD_ETHER) {
+               int pad = ETH_ZLEN - skb->len;
+
+               if (pad > 0) { /* Pad the frame with zeros */
+                       if (__skb_pad(skb, pad, false))
+                               goto drop;
+                       skb_put(skb, pad);
                }
        }
 
+       skb->dev = dev;
+       if (fr_hard_header(&skb, pvc->dlci))
+               goto drop;
+
+       dev->stats.tx_bytes += skb->len;
+       dev->stats.tx_packets++;
+       if (pvc->state.fecn) /* TX Congestion counter */
+               dev->stats.tx_compressed++;
+       skb->dev = pvc->frad;
+       skb->protocol = htons(ETH_P_HDLC);
+       skb_reset_network_header(skb);
+       dev_queue_xmit(skb);
+       return NETDEV_TX_OK;
+
+drop:
        dev->stats.tx_dropped++;
-       dev_kfree_skb(skb);
+       kfree_skb(skb);
        return NETDEV_TX_OK;
 }