net: Remove all uses of LL_ALLOCATED_SPACE

net: Remove all uses of LL_ALLOCATED_SPACE

The macro LL_ALLOCATED_SPACE was ill-conceived.  It applies the
alignment to the sum of needed_headroom and needed_tailroom.  As
the amount that is then reserved for head room is needed_headroom
with alignment, this means that the tail room left may be too small.

This patch replaces all uses of LL_ALLOCATED_SPACE with the macro
LL_RESERVED_SPACE and direct reference to needed_tailroom.

This also fixes the problem with needed_headroom changing between
allocating the skb and reserving the head room.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 7 deletions

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 82a6f34..71c1a75 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1944,7 +1944,7 @@ static void tpacket_destruct_skb(struct sk_buff *skb)
 
 static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
 		void *frame, struct net_device *dev, int size_max,
-		__be16 proto, unsigned char *addr)
+		__be16 proto, unsigned char *addr, int hlen)
 {
 	union {
 		struct tpacket_hdr *h1;
@@ -1978,7 +1978,7 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
 		return -EMSGSIZE;
 	}
 
-	skb_reserve(skb, LL_RESERVED_SPACE(dev));
+	skb_reserve(skb, hlen);
 	skb_reset_network_header(skb);
 
 	data = ph.raw + po->tp_hdrlen - sizeof(struct sockaddr_ll);
@@ -2053,6 +2053,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
 	unsigned char *addr;
 	int len_sum = 0;
 	int status = 0;
+	int hlen, tlen;
 
 	mutex_lock(&po->pg_vec_lock);
 
@@ -2101,16 +2102,17 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
 		}
 
 		status = TP_STATUS_SEND_REQUEST;
+		hlen = LL_RESERVED_SPACE(dev);
+		tlen = dev->needed_tailroom;
 		skb = sock_alloc_send_skb(&po->sk,
-				LL_ALLOCATED_SPACE(dev)
-				+ sizeof(struct sockaddr_ll),
+				hlen + tlen + sizeof(struct sockaddr_ll),
 				0, &err);
 
 		if (unlikely(skb == NULL))
 			goto out_status;
 
 		tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto,
-				addr);
+				addr, hlen);
 
 		if (unlikely(tp_len < 0)) {
 			if (po->tp_loss) {
@@ -2207,6 +2209,7 @@ static int packet_snd(struct socket *sock,
 	int vnet_hdr_len;
 	struct packet_sock *po = pkt_sk(sk);
 	unsigned short gso_type = 0;
+	int hlen, tlen;
 
 	/*
 	 *	Get and verify the address.
@@ -2291,8 +2294,9 @@ static int packet_snd(struct socket *sock,
 		goto out_unlock;
 
 	err = -ENOBUFS;
-	skb = packet_alloc_skb(sk, LL_ALLOCATED_SPACE(dev),
-			       LL_RESERVED_SPACE(dev), len, vnet_hdr.hdr_len,
+	hlen = LL_RESERVED_SPACE(dev);
+	tlen = dev->needed_tailroom;
+	skb = packet_alloc_skb(sk, hlen + tlen, hlen, len, vnet_hdr.hdr_len,
 			       msg->msg_flags & MSG_DONTWAIT, &err);
 	if (skb == NULL)
 		goto out_unlock;