[PATCH] aoe: reserve enough headroom on skbs

[Eric Dumazet <eric.dumazet@gmail.com>]

From: Eric Dumazet <edumazet@google.com>

Some network drivers use a non default hard_header_len

Transmitted skb should take into account dev->hard_header_len, or risk
crashes or expensive reallocations.

In the case of aoe, lets reserve MAX_HEADER bytes.

David reported a crash in defxx driver, solved by this patch.

Reported-by: David Oostdyk <daveo@ll.mit.edu>
Tested-by: David Oostdyk <daveo@ll.mit.edu>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ed Cashin <ecashin@coraid.com>
---
 drivers/block/aoe/aoecmd.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index 25ef5c0..92b6d7c 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -51,8 +51,9 @@ new_skb(ulong len)
 {
 	struct sk_buff *skb;
 
-	skb = alloc_skb(len, GFP_ATOMIC);
+	skb = alloc_skb(len + MAX_HEADER, GFP_ATOMIC);
 	if (skb) {
+		skb_reserve(skb, MAX_HEADER);
 		skb_reset_mac_header(skb);
 		skb_reset_network_header(skb);
 		skb->protocol = __constant_htons(ETH_P_AOE);