networking: make skb_push & __skb_push return void pointers

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions return void * and remove all the casts across
the tree, adding a (u8 *) cast only where the unsigned char pointer
was used directly, all done with the following spatch:

    @@
    expression SKB, LEN;
    typedef u8;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    @@
    - *(fn(SKB, LEN))
    + *(u8 *)fn(SKB, LEN)

    @@
    expression E, SKB, LEN;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    type T;
    @@
    - E = ((T *)(fn(SKB, LEN)))
    + E = fn(SKB, LEN)

    @@
    expression SKB, LEN;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    @@
    - fn(SKB, LEN)[0]
    + *(u8 *)fn(SKB, LEN)

Note that the last part there converts from push(...)[0] to the
more idiomatic *(u8 *)push(...).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 7 insertions, 7 deletions

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index 5274501428e4..5333601f855f 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -1099,7 +1099,7 @@ static struct sk_buff *bcm_sysport_insert_tsb(struct sk_buff *skb,
 		skb = nskb;
 	}
 
-	tsb = (struct bcm_tsb *)skb_push(skb, sizeof(*tsb));
+	tsb = skb_push(skb, sizeof(*tsb));
 	/* Zero-out TSB by default */
 	memset(tsb, 0, sizeof(*tsb));
 
diff --git a/drivers/net/ethernet/chelsio/cxgb/sge.c b/drivers/net/ethernet/chelsio/cxgb/sge.c
index d56142b98534..0f13a7f7c1d3 100644
--- a/drivers/net/ethernet/chelsio/cxgb/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb/sge.c
@@ -1801,7 +1801,7 @@ netdev_tx_t t1_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		eth_type = skb_network_offset(skb) == ETH_HLEN ?
 			CPL_ETH_II : CPL_ETH_II_VLAN;
 
-		hdr = (struct cpl_tx_pkt_lso *)skb_push(skb, sizeof(*hdr));
+		hdr = skb_push(skb, sizeof(*hdr));
 		hdr->opcode = CPL_TX_PKT_LSO;
 		hdr->ip_csum_dis = hdr->l4_csum_dis = 0;
 		hdr->ip_hdr_words = ip_hdr(skb)->ihl;
@@ -1849,7 +1849,7 @@ netdev_tx_t t1_start_xmit(struct sk_buff *skb, struct net_device *dev)
 			}
 		}
 
-		cpl = (struct cpl_tx_pkt *)__skb_push(skb, sizeof(*cpl));
+		cpl = __skb_push(skb, sizeof(*cpl));
 		cpl->opcode = CPL_TX_PKT;
 		cpl->ip_csum_dis = 1;    /* SW calculates IP csum */
 		cpl->l4_csum_dis = skb->ip_summed == CHECKSUM_PARTIAL ? 0 : 1;
diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index 0ff166ec3e7e..a79e257bc338 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -2250,7 +2250,7 @@ static int gfar_enet_open(struct net_device *dev)
 
 static inline struct txfcb *gfar_add_fcb(struct sk_buff *skb)
 {
-	struct txfcb *fcb = (struct txfcb *)skb_push(skb, GMAC_FCB_LEN);
+	struct txfcb *fcb = skb_push(skb, GMAC_FCB_LEN);
 
 	memset(fcb, 0, GMAC_FCB_LEN);
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c b/drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c
index c456ca07b562..898759fcf9ec 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c
@@ -132,7 +132,7 @@ static struct sk_buff *mlx5e_test_get_udp_skb(struct mlx5e_priv *priv)
 	skb_reserve(skb, NET_IP_ALIGN);
 
 	/*  Reserve for ethernet and IP header  */
-	ethh = (struct ethhdr *)skb_push(skb, ETH_HLEN);
+	ethh = skb_push(skb, ETH_HLEN);
 	skb_reset_mac_header(skb);
 
 	skb_set_network_header(skb, skb->len);
diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
index 2dcca249eb9c..46cb7f8955a2 100644
--- a/drivers/net/ethernet/sun/niu.c
+++ b/drivers/net/ethernet/sun/niu.c
@@ -6667,7 +6667,7 @@ static netdev_tx_t niu_start_xmit(struct sk_buff *skb,
 	headroom = align + sizeof(struct tx_pkt_hdr);
 
 	ehdr = (struct ethhdr *) skb->data;
-	tp = (struct tx_pkt_hdr *) skb_push(skb, headroom);
+	tp = skb_push(skb, headroom);
 
 	len = skb->len - sizeof(struct tx_pkt_hdr);
 	tp->flags = cpu_to_le64(niu_compute_tx_flags(skb, ehdr, align, len));
diff --git a/drivers/net/ethernet/toshiba/ps3_gelic_net.c b/drivers/net/ethernet/toshiba/ps3_gelic_net.c
index fa6a06571187..88d74aef218a 100644
--- a/drivers/net/ethernet/toshiba/ps3_gelic_net.c
+++ b/drivers/net/ethernet/toshiba/ps3_gelic_net.c
@@ -754,7 +754,7 @@ static struct sk_buff *gelic_put_vlan_tag(struct sk_buff *skb,
 			return NULL;
 		dev_kfree_skb_any(sk_tmp);
 	}
-	veth = (struct vlan_ethhdr *)skb_push(skb, VLAN_HLEN);
+	veth = skb_push(skb, VLAN_HLEN);
 
 	/* Move the mac addresses to the top of buffer */
 	memmove(skb->data, skb->data + VLAN_HLEN, 2 * ETH_ALEN);