[NETLINK]: Introduce nlmsg_hdr() helper

For the common "(struct nlmsghdr *)skb->data" sequence, so that we reduce the
number of direct accesses to skb->data and for consistency with all the other
cast skb member helpers.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

15 files changed, 23 insertions, 18 deletions

diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index a905f7820331..7f9c4fb7e5b0 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -212,7 +212,7 @@ static void cn_rx_skb(struct sk_buff *__skb)
         skb = skb_get(__skb);
 
         if (skb->len >= NLMSG_SPACE(0)) {
-                nlh = (struct nlmsghdr *)skb->data;
+                nlh = nlmsg_hdr(skb);
 
                 if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
                     skb->len < nlh->nlmsg_len ||
diff --git a/drivers/scsi/scsi_netlink.c b/drivers/scsi/scsi_netlink.c
index 1b59b27e887f..45646a285244 100644
--- a/drivers/scsi/scsi_netlink.c
+++ b/drivers/scsi/scsi_netlink.c
@@ -50,7 +50,7 @@ scsi_nl_rcv_msg(struct sk_buff *skb)
         while (skb->len >= NLMSG_SPACE(0)) {
                 err = 0;
 
-                nlh = (struct nlmsghdr *) skb->data;
+                nlh = nlmsg_hdr(skb);
                 if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
                     (skb->len < nlh->nlmsg_len)) {
                         printk(KERN_WARNING "%s: discarding partial skb\n",
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index ce0d14af33c8..10590cd7e9ed 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -1081,7 +1081,7 @@ iscsi_if_rx(struct sock *sk, int len)
                         struct nlmsghdr *nlh;
                         struct iscsi_uevent *ev;
 
-                        nlh = (struct nlmsghdr *)skb->data;
+                        nlh = nlmsg_hdr(skb);
                         if (nlh->nlmsg_len < sizeof(*nlh) ||
                             skb->len < nlh->nlmsg_len) {
                                 break;
diff --git a/fs/ecryptfs/netlink.c b/fs/ecryptfs/netlink.c
index e3aa2253c850..8405d216a5fc 100644
--- a/fs/ecryptfs/netlink.c
+++ b/fs/ecryptfs/netlink.c
@@ -97,7 +97,7 @@ out:
  */
 static int ecryptfs_process_nl_response(struct sk_buff *skb)
 {
-        struct nlmsghdr *nlh = (struct nlmsghdr*)skb->data;
+        struct nlmsghdr *nlh = nlmsg_hdr(skb);
         struct ecryptfs_message *msg = NLMSG_DATA(nlh);
         int rc;
 
@@ -181,7 +181,7 @@ receive:
                                 "rc = [%d]\n", rc);
                 return;
         }
-        nlh = (struct nlmsghdr *)skb->data;
+        nlh = nlmsg_hdr(skb);
         if (!NLMSG_OK(nlh, skb->len)) {
                 ecryptfs_printk(KERN_ERR, "Received corrupt netlink "
                                 "message\n");
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 68a632b372ec..36629fff26d3 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -138,6 +138,11 @@ struct nlattr
 #include <linux/capability.h>
 #include <linux/skbuff.h>
 
+static inline struct nlmsghdr *nlmsg_hdr(const struct sk_buff *skb)
+{
+        return (struct nlmsghdr *)skb->data;
+}
+
 struct netlink_skb_parms
 {
         struct ucred            creds;          /* Skb credentials      */
diff --git a/kernel/audit.c b/kernel/audit.c
index ea8521417d13..80a7457dadbf 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -151,7 +151,7 @@ struct audit_buffer {
 
 static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
 {
-        struct nlmsghdr *nlh = (struct nlmsghdr *)ab->skb->data;
+        struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
         nlh->nlmsg_pid = pid;
 }
 
@@ -750,7 +750,7 @@ static void audit_receive_skb(struct sk_buff *skb)
         u32             rlen;
 
         while (skb->len >= NLMSG_SPACE(0)) {
-                nlh = (struct nlmsghdr *)skb->data;
+                nlh = nlmsg_hdr(skb);
                 if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
                         return;
                 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
@@ -1268,7 +1268,7 @@ void audit_log_end(struct audit_buffer *ab)
                 audit_log_lost("rate limit exceeded");
         } else {
                 if (audit_pid) {
-                        struct nlmsghdr *nlh = (struct nlmsghdr *)ab->skb->data;
+                        struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
                         nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
                         skb_queue_tail(&audit_skb_queue, ab->skb);
                         ab->skb = NULL;
diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index 4c3476fa058d..ad7d2392cb0e 100644
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -102,7 +102,7 @@ static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
  */
 static int send_reply(struct sk_buff *skb, pid_t pid)
 {
-        struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
+        struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
         void *reply = genlmsg_data(genlhdr);
         int rc;
 
@@ -121,7 +121,7 @@ static int send_reply(struct sk_buff *skb, pid_t pid)
 static void send_cpu_listeners(struct sk_buff *skb,
                                         struct listener_list *listeners)
 {
-        struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
+        struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
         struct listener *s, *tmp;
         struct sk_buff *skb_next, *skb_cur = skb;
         void *reply = genlmsg_data(genlhdr);
diff --git a/net/decnet/netfilter/dn_rtmsg.c b/net/decnet/netfilter/dn_rtmsg.c
index ceefd9dd0c92..9e8256a2361e 100644
--- a/net/decnet/netfilter/dn_rtmsg.c
+++ b/net/decnet/netfilter/dn_rtmsg.c
@@ -102,7 +102,7 @@ static unsigned int dnrmg_hook(unsigned int hook,
 
 static inline void dnrmg_receive_user_skb(struct sk_buff *skb)
 {
-        struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
+        struct nlmsghdr *nlh = nlmsg_hdr(skb);
 
         if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
                 return;
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index cac06c43f004..3ff753c6f197 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -807,7 +807,7 @@ static void nl_fib_input(struct sock *sk, int len)
         if (skb == NULL)
                 return;
 
-        nlh = (struct nlmsghdr *)skb->data;
+        nlh = nlmsg_hdr(skb);
         if (skb->len < NLMSG_SPACE(0) || skb->len < nlh->nlmsg_len ||
             nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn))) {
                 kfree_skb(skb);
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 37362cd1d07f..238999e6e871 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -847,7 +847,7 @@ static inline void inet_diag_rcv_skb(struct sk_buff *skb)
 {
         if (skb->len >= NLMSG_SPACE(0)) {
                 int err;
-                struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
+                struct nlmsghdr *nlh = nlmsg_hdr(skb);
 
                 if (nlh->nlmsg_len < sizeof(*nlh) ||
                     skb->len < nlh->nlmsg_len)
diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c
index 15e0d2002235..17f7c988460c 100644
--- a/net/ipv4/netfilter/ip_queue.c
+++ b/net/ipv4/netfilter/ip_queue.c
@@ -497,7 +497,7 @@ ipq_rcv_skb(struct sk_buff *skb)
         if (skblen < sizeof(*nlh))
                 return;
 
-        nlh = (struct nlmsghdr *)skb->data;
+        nlh = nlmsg_hdr(skb);
         nlmsglen = nlh->nlmsg_len;
         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
                 return;
diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index 5cfce218c5e1..275e625e4977 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c
@@ -487,7 +487,7 @@ ipq_rcv_skb(struct sk_buff *skb)
         if (skblen < sizeof(*nlh))
                 return;
 
-        nlh = (struct nlmsghdr *)skb->data;
+        nlh = nlmsg_hdr(skb);
         nlmsglen = nlh->nlmsg_len;
         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
                 return;
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 50dc5edb7752..04b72d3c1dea 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1471,7 +1471,7 @@ static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
         int err;
 
         while (skb->len >= nlmsg_total_size(0)) {
-                nlh = (struct nlmsghdr *) skb->data;
+                nlh = nlmsg_hdr(skb);
 
                 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
                         return 0;
diff --git a/net/tipc/netlink.c b/net/tipc/netlink.c
index b8e1edc2badc..4cdafa2d1d4d 100644
--- a/net/tipc/netlink.c
+++ b/net/tipc/netlink.c
@@ -57,7 +57,7 @@ static int handle_cmd(struct sk_buff *skb, struct genl_info *info)
 
         if (rep_buf) {
                 skb_push(rep_buf, hdr_space);
-                rep_nlh = (struct nlmsghdr *)rep_buf->data;
+                rep_nlh = nlmsg_hdr(rep_buf);
                 memcpy(rep_nlh, req_nlh, hdr_space);
                 rep_nlh->nlmsg_len = rep_buf->len;
                 genlmsg_unicast(rep_buf, req_nlh->nlmsg_pid);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index addb58501057..5f02b4be1917 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3786,7 +3786,7 @@ static int selinux_nlmsg_perm(struct sock *sk, struct sk_buff *skb)
                 err = -EINVAL;
                 goto out;
         }
-        nlh = (struct nlmsghdr *)skb->data;
+        nlh = nlmsg_hdr(skb);
         
         err = selinux_nlmsg_lookup(isec->sclass, nlh->nlmsg_type, &perm);
         if (err) {