batman-adv: Consume skb in batadv_frag_send_packet

Sending functions in Linux consume the supplied skbuff. Doing the same in
batadv_frag_send_packet avoids the hack of returning -1 (-EPERM) to signal
the caller that he is responsible for cleaning up the skb.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index a2e28a1..9c561e6 100644 (file)
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -20,6 +20,7 @@
 
 #include <linux/atomic.h>
 #include <linux/byteorder/generic.h>
+#include <linux/errno.h>
 #include <linux/etherdevice.h>
 #include <linux/fs.h>
 #include <linux/if_ether.h>
@@ -441,8 +442,7 @@ err:
  * @orig_node: final destination of the created fragments
  * @neigh_node: next-hop of the created fragments
  *
- * Return: the netdev tx status or -1 in case of error.
- * When -1 is returned the skb is not consumed.
+ * Return: the netdev tx status or a negative errno code on a failure
  */
 int batadv_frag_send_packet(struct sk_buff *skb,
                            struct batadv_orig_node *orig_node,
@@ -455,7 +455,7 @@ int batadv_frag_send_packet(struct sk_buff *skb,
        unsigned int mtu = neigh_node->if_incoming->net_dev->mtu;
        unsigned int header_size = sizeof(frag_header);
        unsigned int max_fragment_size, max_packet_size;
-       int ret = -1;
+       int ret;
 
        /* To avoid merge and refragmentation at next-hops we never send
         * fragments larger than BATADV_FRAG_MAX_FRAG_SIZE
@@ -465,13 +465,17 @@ int batadv_frag_send_packet(struct sk_buff *skb,
        max_packet_size = max_fragment_size * BATADV_FRAG_MAX_FRAGMENTS;
 
        /* Don't even try to fragment, if we need more than 16 fragments */
-       if (skb->len > max_packet_size)
-               goto out;
+       if (skb->len > max_packet_size) {
+               ret = -EAGAIN;
+               goto free_skb;
+       }
 
        bat_priv = orig_node->bat_priv;
        primary_if = batadv_primary_if_get_selected(bat_priv);
-       if (!primary_if)
-               goto out;
+       if (!primary_if) {
+               ret = -EINVAL;
+               goto put_primary_if;
+       }
 
        /* Create one header to be copied to all fragments */
        frag_header.packet_type = BATADV_UNICAST_FRAG;
@@ -496,34 +500,35 @@ int batadv_frag_send_packet(struct sk_buff *skb,
        /* Eat and send fragments from the tail of skb */
        while (skb->len > max_fragment_size) {
                skb_fragment = batadv_frag_create(skb, &frag_header, mtu);
-               if (!skb_fragment)
-                       goto out;
+               if (!skb_fragment) {
+                       ret = -ENOMEM;
+                       goto free_skb;
+               }
 
                batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_TX);
                batadv_add_counter(bat_priv, BATADV_CNT_FRAG_TX_BYTES,
                                   skb_fragment->len + ETH_HLEN);
                ret = batadv_send_unicast_skb(skb_fragment, neigh_node);
                if (ret != NET_XMIT_SUCCESS) {
-                       /* return -1 so that the caller can free the original
-                        * skb
-                        */
-                       ret = -1;
-                       goto out;
+                       ret = NET_XMIT_DROP;
+                       goto free_skb;
                }
 
                frag_header.no++;
 
                /* The initial check in this function should cover this case */
                if (frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1) {
-                       ret = -1;
-                       goto out;
+                       ret = -EINVAL;
+                       goto free_skb;
                }
        }
 
        /* Make room for the fragment header. */
        if (batadv_skb_head_push(skb, header_size) < 0 ||
-           pskb_expand_head(skb, header_size + ETH_HLEN, 0, GFP_ATOMIC) < 0)
-               goto out;
+           pskb_expand_head(skb, header_size + ETH_HLEN, 0, GFP_ATOMIC) < 0) {
+               ret = -ENOMEM;
+               goto free_skb;
+       }
 
        memcpy(skb->data, &frag_header, header_size);
 
@@ -532,10 +537,13 @@ int batadv_frag_send_packet(struct sk_buff *skb,
        batadv_add_counter(bat_priv, BATADV_CNT_FRAG_TX_BYTES,
                           skb->len + ETH_HLEN);
        ret = batadv_send_unicast_skb(skb, neigh_node);
+       /* skb was consumed */
+       skb = NULL;
 
-out:
-       if (primary_if)
-               batadv_hardif_put(primary_if);
+put_primary_if:
+       batadv_hardif_put(primary_if);
+free_skb:
+       kfree_skb(skb);
 
        return ret;
 }