batman-adv: Reserve extra bytes in skb for better alignment

The ethernet header is 14 bytes long. Therefore, the data after it is not 4
byte aligned and may cause problems on systems without unaligned data access.
Reserving NET_IP_ALIGN more byes can fix the misalignment of the ethernet
header.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/net/batman-adv/vis.c b/net/batman-adv/vis.c
index 5abd1454fb0..ad14a6c91d6 100644
--- a/net/batman-adv/vis.c
+++ b/net/batman-adv/vis.c
@@ -396,12 +396,12 @@ batadv_add_packet(struct batadv_priv *bat_priv,
                 return NULL;
 
         len = sizeof(*packet) + vis_info_len;
-        info->skb_packet = dev_alloc_skb(len + ETH_HLEN);
+        info->skb_packet = dev_alloc_skb(len + ETH_HLEN + NET_IP_ALIGN);
         if (!info->skb_packet) {
                 kfree(info);
                 return NULL;
         }
-        skb_reserve(info->skb_packet, ETH_HLEN);
+        skb_reserve(info->skb_packet, ETH_HLEN + NET_IP_ALIGN);
         packet = (struct batadv_vis_packet *)skb_put(info->skb_packet, len);
 
         kref_init(&info->refcount);
@@ -873,12 +873,13 @@ int batadv_vis_init(struct batadv_priv *bat_priv)
         if (!bat_priv->vis.my_info)
                 goto err;
 
-        len = sizeof(*packet) + BATADV_MAX_VIS_PACKET_SIZE + ETH_HLEN;
+        len = sizeof(*packet) + BATADV_MAX_VIS_PACKET_SIZE;
+        len += ETH_HLEN + NET_IP_ALIGN;
         bat_priv->vis.my_info->skb_packet = dev_alloc_skb(len);
         if (!bat_priv->vis.my_info->skb_packet)
                 goto free_info;
 
-        skb_reserve(bat_priv->vis.my_info->skb_packet, ETH_HLEN);
+        skb_reserve(bat_priv->vis.my_info->skb_packet, ETH_HLEN + NET_IP_ALIGN);
         tmp_skb = bat_priv->vis.my_info->skb_packet;
         packet = (struct batadv_vis_packet *)skb_put(tmp_skb, sizeof(*packet));