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>

83 files changed, 135 insertions, 161 deletions

diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c
index 4fc99ae1c534..c8f2ca6d8b29 100644
--- a/drivers/atm/solos-pci.c
+++ b/drivers/atm/solos-pci.c
@@ -1174,7 +1174,7 @@ static int psend(struct atm_vcc *vcc, struct sk_buff *skb)
 		}
 	}
 
-	header = (void *)skb_push(skb, sizeof(*header));
+	header = skb_push(skb, sizeof(*header));
 
 	/* This does _not_ include the size of the header */
 	header->size = cpu_to_le16(pktlen);
diff --git a/drivers/bluetooth/bpa10x.c b/drivers/bluetooth/bpa10x.c
index a9932fe57d92..48d10cb5c9a1 100644
--- a/drivers/bluetooth/bpa10x.c
+++ b/drivers/bluetooth/bpa10x.c
@@ -297,7 +297,7 @@ static int bpa10x_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
 		return -ENOMEM;
 
 	/* Prepend skb with frame type */
-	*skb_push(skb, 1) = hci_skb_pkt_type(skb);
+	*(u8 *)skb_push(skb, 1) = hci_skb_pkt_type(skb);
 
 	switch (hci_skb_pkt_type(skb)) {
 	case HCI_COMMAND_PKT:
diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c
index d5040bbd34e8..242359c2d1f1 100644
--- a/drivers/firewire/net.c
+++ b/drivers/firewire/net.c
@@ -219,7 +219,7 @@ static int fwnet_header_create(struct sk_buff *skb, struct net_device *net,
 {
 	struct fwnet_header *h;
 
-	h = (struct fwnet_header *)skb_push(skb, sizeof(*h));
+	h = skb_push(skb, sizeof(*h));
 	put_unaligned_be16(type, &h->h_proto);
 
 	if (net->flags & (IFF_LOOPBACK | IFF_NOARP)) {
@@ -961,16 +961,14 @@ static int fwnet_send_packet(struct fwnet_packet_task *ptask)
 	tx_len = ptask->max_payload;
 	switch (fwnet_get_hdr_lf(&ptask->hdr)) {
 	case RFC2374_HDR_UNFRAG:
-		bufhdr = (struct rfc2734_header *)
-				skb_push(ptask->skb, RFC2374_UNFRAG_HDR_SIZE);
+		bufhdr = skb_push(ptask->skb, RFC2374_UNFRAG_HDR_SIZE);
 		put_unaligned_be32(ptask->hdr.w0, &bufhdr->w0);
 		break;
 
 	case RFC2374_HDR_FIRSTFRAG:
 	case RFC2374_HDR_INTFRAG:
 	case RFC2374_HDR_LASTFRAG:
-		bufhdr = (struct rfc2734_header *)
-				skb_push(ptask->skb, RFC2374_FRAG_HDR_SIZE);
+		bufhdr = skb_push(ptask->skb, RFC2374_FRAG_HDR_SIZE);
 		put_unaligned_be32(ptask->hdr.w0, &bufhdr->w0);
 		put_unaligned_be32(ptask->hdr.w1, &bufhdr->w1);
 		break;
diff --git a/drivers/infiniband/hw/cxgb3/iwch_cm.c b/drivers/infiniband/hw/cxgb3/iwch_cm.c
index 9ae518c01bc2..86975370a4c0 100644
--- a/drivers/infiniband/hw/cxgb3/iwch_cm.c
+++ b/drivers/infiniband/hw/cxgb3/iwch_cm.c
@@ -513,7 +513,7 @@ static void send_mpa_req(struct iwch_ep *ep, struct sk_buff *skb)
 	set_arp_failure_handler(skb, arp_failure_discard);
 	skb_reset_transport_header(skb);
 	len = skb->len;
-	req = (struct tx_data_wr *) skb_push(skb, sizeof(*req));
+	req = skb_push(skb, sizeof(*req));
 	req->wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_TX_DATA)|F_WR_COMPL);
 	req->wr_lo = htonl(V_WR_TID(ep->hwtid));
 	req->len = htonl(len);
@@ -564,7 +564,7 @@ static int send_mpa_reject(struct iwch_ep *ep, const void *pdata, u8 plen)
 	skb->priority = CPL_PRIORITY_DATA;
 	set_arp_failure_handler(skb, arp_failure_discard);
 	skb_reset_transport_header(skb);
-	req = (struct tx_data_wr *) skb_push(skb, sizeof(*req));
+	req = skb_push(skb, sizeof(*req));
 	req->wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_TX_DATA)|F_WR_COMPL);
 	req->wr_lo = htonl(V_WR_TID(ep->hwtid));
 	req->len = htonl(mpalen);
@@ -615,7 +615,7 @@ static int send_mpa_reply(struct iwch_ep *ep, const void *pdata, u8 plen)
 	set_arp_failure_handler(skb, arp_failure_discard);
 	skb_reset_transport_header(skb);
 	len = skb->len;
-	req = (struct tx_data_wr *) skb_push(skb, sizeof(*req));
+	req = skb_push(skb, sizeof(*req));
 	req->wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_TX_DATA)|F_WR_COMPL);
 	req->wr_lo = htonl(V_WR_TID(ep->hwtid));
 	req->len = htonl(len);
diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c
index 36ae3023e703..76fb39415e18 100644
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -3751,7 +3751,7 @@ static void build_cpl_pass_accept_req(struct sk_buff *skb, int stid , u8 tos)
 	tcp_clear_options(&tmp_opt);
 	tcp_parse_options(&init_net, skb, &tmp_opt, 0, NULL);
 
-	req = (struct cpl_pass_accept_req *)__skb_push(skb, sizeof(*req));
+	req = __skb_push(skb, sizeof(*req));
 	memset(req, 0, sizeof(*req));
 	req->l2info = cpu_to_be16(SYN_INTF_V(intf) |
 			 SYN_MAC_IDX_V(RX_MACIDX_G(
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index a115c0b7a310..5da6f2e9f22e 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -681,7 +681,7 @@ static void push_pseudo_header(struct sk_buff *skb, const char *daddr)
 {
 	struct ipoib_pseudo_header *phdr;
 
-	phdr = (struct ipoib_pseudo_header *)skb_push(skb, sizeof(*phdr));
+	phdr = skb_push(skb, sizeof(*phdr));
 	memcpy(phdr->hwaddr, daddr, INFINIBAND_ALEN);
 }
 
@@ -1129,7 +1129,7 @@ static int ipoib_hard_header(struct sk_buff *skb,
 {
 	struct ipoib_header *header;
 
-	header = (struct ipoib_header *) skb_push(skb, sizeof *header);
+	header = skb_push(skb, sizeof *header);
 
 	header->proto = htons(type);
 	header->reserved = 0;
diff --git a/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.c b/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.c
index 2e8fee982436..afa938bd26d6 100644
--- a/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.c
+++ b/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.c
@@ -460,7 +460,7 @@ void opa_vnic_encap_skb(struct opa_vnic_adapter *adapter, struct sk_buff *skb)
 	sc = opa_vnic_get_sc(info, skb);
 	l4_hdr = info->vesw.vesw_id;
 
-	mdata = (struct opa_vnic_skb_mdata *)skb_push(skb, sizeof(*mdata));
+	mdata = skb_push(skb, sizeof(*mdata));
 	mdata->vl = opa_vnic_get_vl(adapter, skb);
 	mdata->entropy = entropy;
 	mdata->flags = 0;
diff --git a/drivers/infiniband/ulp/opa_vnic/opa_vnic_netdev.c b/drivers/infiniband/ulp/opa_vnic/opa_vnic_netdev.c
index 905f39dda5aa..fcf75323d62a 100644
--- a/drivers/infiniband/ulp/opa_vnic/opa_vnic_netdev.c
+++ b/drivers/infiniband/ulp/opa_vnic/opa_vnic_netdev.c
@@ -103,7 +103,7 @@ static u16 opa_vnic_select_queue(struct net_device *netdev, struct sk_buff *skb,
 	int rc;
 
 	/* pass entropy and vl as metadata in skb */
-	mdata = (struct opa_vnic_skb_mdata *)skb_push(skb, sizeof(*mdata));
+	mdata = skb_push(skb, sizeof(*mdata));
 	mdata->entropy =  opa_vnic_calc_entropy(adapter, skb);
 	mdata->vl = opa_vnic_get_vl(adapter, skb);
 	rc = adapter->rn_ops->ndo_select_queue(netdev, skb,
diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
index e26cae9baf17..b7e3f1cde683 100644
--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -1312,7 +1312,7 @@ isdn_ppp_xmit(struct sk_buff *skb, struct net_device *netdev)
 	/* check if we should pass this packet
 	 * the filter instructions are constructed assuming
 	 * a four-byte PPP header on each packet */
-	*skb_push(skb, 4) = 1; /* indicate outbound */
+	*(u8 *)skb_push(skb, 4) = 1; /* indicate outbound */
 
 	{
 		__be16 *p = (__be16 *)skb->data;
diff --git a/drivers/net/arcnet/arc-rawmode.c b/drivers/net/arcnet/arc-rawmode.c
index d78f30186642..8c651fdee039 100644
--- a/drivers/net/arcnet/arc-rawmode.c
+++ b/drivers/net/arcnet/arc-rawmode.c
@@ -85,7 +85,7 @@ static int build_header(struct sk_buff *skb, struct net_device *dev,
 			unsigned short type, uint8_t daddr)
 {
 	int hdr_size = ARC_HDR_SIZE;
-	struct archdr *pkt = (struct archdr *)skb_push(skb, hdr_size);
+	struct archdr *pkt = skb_push(skb, hdr_size);
 
 	/* Set the source hardware address.
 	 *
diff --git a/drivers/net/arcnet/capmode.c b/drivers/net/arcnet/capmode.c
index 2056878fb087..a80f4eb9262d 100644
--- a/drivers/net/arcnet/capmode.c
+++ b/drivers/net/arcnet/capmode.c
@@ -101,7 +101,7 @@ static int build_header(struct sk_buff *skb,
 			uint8_t daddr)
 {
 	int hdr_size = ARC_HDR_SIZE;
-	struct archdr *pkt = (struct archdr *)skb_push(skb, hdr_size);
+	struct archdr *pkt = skb_push(skb, hdr_size);
 
 	arc_printk(D_PROTO, dev, "Preparing header for cap packet %x.\n",
 		   *((int *)&pkt->soft.cap.cookie[0]));
diff --git a/drivers/net/arcnet/rfc1051.c b/drivers/net/arcnet/rfc1051.c
index 4b1a75469cb1..a7752a5b647f 100644
--- a/drivers/net/arcnet/rfc1051.c
+++ b/drivers/net/arcnet/rfc1051.c
@@ -162,7 +162,7 @@ static int build_header(struct sk_buff *skb, struct net_device *dev,
 			unsigned short type, uint8_t daddr)
 {
 	int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE;
-	struct archdr *pkt = (struct archdr *)skb_push(skb, hdr_size);
+	struct archdr *pkt = skb_push(skb, hdr_size);
 	struct arc_rfc1051 *soft = &pkt->soft.rfc1051;
 
 	/* set the protocol ID according to RFC1051 */
diff --git a/drivers/net/arcnet/rfc1201.c b/drivers/net/arcnet/rfc1201.c
index 566da5ecdc9d..a4c856282674 100644
--- a/drivers/net/arcnet/rfc1201.c
+++ b/drivers/net/arcnet/rfc1201.c
@@ -379,7 +379,7 @@ static int build_header(struct sk_buff *skb, struct net_device *dev,
 {
 	struct arcnet_local *lp = netdev_priv(dev);
 	int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
-	struct archdr *pkt = (struct archdr *)skb_push(skb, hdr_size);
+	struct archdr *pkt = skb_push(skb, hdr_size);
 	struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
 
 	/* set the protocol ID according to RFC1201 */
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 2dcc