networking: make skb_pull & friends 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_pull,
            __skb_pull,
            skb_pull_inline,
            __pskb_pull_tail,
            __pskb_pull,
            pskb_pull
    };
    @@
    - *(fn(SKB, LEN))
    + *(u8 *)fn(SKB, LEN)

    @@
    expression E, SKB, LEN;
    identifier fn = {
            skb_pull,
            __skb_pull,
            skb_pull_inline,
            __pskb_pull_tail,
            __pskb_pull,
            pskb_pull
    };
    type T;
    @@
    - E = ((T *)(fn(SKB, LEN)))
    + E = fn(SKB, LEN)

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

6 files changed, 15 insertions, 12 deletions

diff --git a/net/bluetooth/a2mp.c b/net/bluetooth/a2mp.c
index f0095fd79818..aad994edd3bb 100644
--- a/net/bluetooth/a2mp.c
+++ b/net/bluetooth/a2mp.c
@@ -239,7 +239,7 @@ static int a2mp_discover_rsp(struct amp_mgr *mgr, struct sk_buff *skb,
 		}
 
 		len -= sizeof(*cl);
-		cl = (void *) skb_pull(skb, sizeof(*cl));
+		cl = skb_pull(skb, sizeof(*cl));
 	}
 
 	/* Fall back to L2CAP init sequence */
@@ -279,7 +279,7 @@ static int a2mp_change_notify(struct amp_mgr *mgr, struct sk_buff *skb,
 	while (skb->len >= sizeof(*cl)) {
 		BT_DBG("Controller id %d type %d status %d", cl->id, cl->type,
 		       cl->status);
-		cl = (struct a2mp_cl *) skb_pull(skb, sizeof(*cl));
+		cl = skb_pull(skb, sizeof(*cl));
 	}
 
 	/* TODO send A2MP_CHANGE_RSP */
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 0baa7f2dd8ef..9a1639f7d61a 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1481,7 +1481,7 @@ EXPORT_SYMBOL(skb_push);
  *	is returned. Once the data has been pulled future pushes will overwrite
  *	the old data.
  */
-unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
+void *skb_pull(struct sk_buff *skb, unsigned int len)
 {
 	return skb_pull_inline(skb, len);
 }
@@ -1616,7 +1616,7 @@ EXPORT_SYMBOL(___pskb_trim);
  *
  * It is pretty complicated. Luckily, it is called only in exceptional cases.
  */
-unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
+void *__pskb_pull_tail(struct sk_buff *skb, int delta)
 {
 	/* If skb has not enough free space at tail, get new one
 	 * plus 128 bytes for future expansions. If we have enough
@@ -3065,7 +3065,7 @@ EXPORT_SYMBOL_GPL(skb_append_pagefrags);
  *	that the checksum difference is zero (e.g., a valid IP header)
  *	or you are setting ip_summed to CHECKSUM_NONE.
  */
-unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
+void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
 {
 	unsigned char *data = skb->data;
 
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index abbd7c992960..3e7454aa49e8 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -669,7 +669,8 @@ static void ipmr_destroy_unres(struct mr_table *mrt, struct mfc_cache *c)
 
 	while ((skb = skb_dequeue(&c->mfc_un.unres.unresolved))) {
 		if (ip_hdr(skb)->version == 0) {
-			struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct iphdr));
+			struct nlmsghdr *nlh = skb_pull(skb,
+							sizeof(struct iphdr));
 			nlh->nlmsg_type = NLMSG_ERROR;
 			nlh->nlmsg_len = nlmsg_msg_size(sizeof(struct nlmsgerr));
 			skb_trim(skb, nlh->nlmsg_len);
@@ -972,7 +973,8 @@ static void ipmr_cache_resolve(struct net *net, struct mr_table *mrt,
 	/* Play the pending entries through our router */
 	while ((skb = __skb_dequeue(&uc->mfc_un.unres.unresolved))) {
 		if (ip_hdr(skb)->version == 0) {
-			struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct iphdr));
+			struct nlmsghdr *nlh = skb_pull(skb,
+							sizeof(struct iphdr));
 
 			if (__ipmr_fill_mroute(mrt, skb, c, nlmsg_data(nlh)) > 0) {
 				nlh->nlmsg_len = skb_tail_pointer(skb) -
diff --git a/net/ipv4/xfrm4_mode_beet.c b/net/ipv4/xfrm4_mode_beet.c
index 71acd0014f2d..856d2dfdb44b 100644
--- a/net/ipv4/xfrm4_mode_beet.c
+++ b/net/ipv4/xfrm4_mode_beet.c
@@ -57,8 +57,7 @@ static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
 
 	xfrm4_beet_make_header(skb);
 
-	ph = (struct ip_beet_phdr *)
-		__skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
+	ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
 
 	top_iph = ip_hdr(skb);
 
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 2ecb39b943b5..b0e2bf1f4212 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -846,7 +846,8 @@ static void ip6mr_destroy_unres(struct mr6_table *mrt, struct mfc6_cache *c)
 
 	while ((skb = skb_dequeue(&c->mfc_un.unres.unresolved)) != NULL) {
 		if (ipv6_hdr(skb)->version == 0) {
-			struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct ipv6hdr));
+			struct nlmsghdr *nlh = skb_pull(skb,
+							sizeof(struct ipv6hdr));
 			nlh->nlmsg_type = NLMSG_ERROR;
 			nlh->nlmsg_len = nlmsg_msg_size(sizeof(struct nlmsgerr));
 			skb_trim(skb, nlh->nlmsg_len);
@@ -1106,7 +1107,8 @@ static void ip6mr_cache_resolve(struct net *net, struct mr6_table *mrt,
 
 	while ((skb = __skb_dequeue(&uc->mfc_un.unres.unresolved))) {
 		if (ipv6_hdr(skb)->version == 0) {
-			struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct ipv6hdr));
+			struct nlmsghdr *nlh = skb_pull(skb,
+							sizeof(struct ipv6hdr));
 
 			if (__ip6mr_fill_mroute(mrt, skb, c, nlmsg_data(nlh)) > 0) {
 				nlh->nlmsg_len = skb_tail_pointer(skb) - (u8 *)nlh;
diff --git a/net/ipv6/xfrm6_mode_beet.c b/net/ipv6/xfrm6_mode_beet.c
index 1e205c3253ac..57fd314ec2b8 100644
--- a/net/ipv6/xfrm6_mode_beet.c
+++ b/net/ipv6/xfrm6_mode_beet.c
@@ -54,7 +54,7 @@ static int xfrm6_beet_output(struct xfrm_state *x, struct sk_buff *skb)
 	skb->mac_header = skb->network_header +
 			  offsetof(struct ipv6hdr, nexthdr);
 	skb->transport_header = skb->network_header + sizeof(*top_iph);
-	ph = (struct ip_beet_phdr *)__skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl-hdr_len);
+	ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdr_len);
 
 	xfrm6_beet_make_header(skb);