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>

4 files changed, 4 insertions, 4 deletions

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 */