[NETLINK]: Remove error pointer from netlink message handler

The error pointer argument in netlink message handlers is used
to signal the special case where processing has to be interrupted
because a dump was started but no error happened. Instead it is
simpler and more clear to return -EINTR and have netlink_run_queue()
deal with getting the queue right.

nfnetlink passed on this error pointer to its subsystem handlers
but only uses it to signal the start of a netlink dump. Therefore
it can be removed there as well.

This patch also cleans up the error handling in the affected
message handlers to be consistent since it had to be touched anyway.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 30 insertions, 52 deletions

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 76f11f32591..443ba7753a3 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -661,7 +661,7 @@ static const size_t cta_min[CTA_MAX] = {
 
 static int
 ctnetlink_del_conntrack(struct sock *ctnl, struct sk_buff *skb,
-			struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+			struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_tuple_hash *h;
 	struct nf_conntrack_tuple tuple;
@@ -709,7 +709,7 @@ ctnetlink_del_conntrack(struct sock *ctnl, struct sk_buff *skb,
 
 static int
 ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb,
-			struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+			struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_tuple_hash *h;
 	struct nf_conntrack_tuple tuple;
@@ -720,22 +720,15 @@ ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb,
 	int err = 0;
 
 	if (nlh->nlmsg_flags & NLM_F_DUMP) {
-		u32 rlen;
-
 #ifndef CONFIG_NF_CT_ACCT
 		if (NFNL_MSG_TYPE(nlh->nlmsg_type) == IPCTNL_MSG_CT_GET_CTRZERO)
 			return -ENOTSUPP;
 #endif
-		if ((*errp = netlink_dump_start(ctnl, skb, nlh,
-						ctnetlink_dump_table,
-						ctnetlink_done)) != 0)
-			return -EINVAL;
-
-		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
-		if (rlen > skb->len)
-			rlen = skb->len;
-		skb_pull(skb, rlen);
-		return 0;
+		err = netlink_dump_start(ctnl, skb, nlh, ctnetlink_dump_table,
+					 ctnetlink_done);
+		if (err == 0)
+			err = -EINTR;
+		return err;
 	}
 
 	if (nfattr_bad_size(cda, CTA_MAX, cta_min))
@@ -1009,7 +1002,7 @@ err:
 
 static int
 ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
-			struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+			struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_tuple otuple, rtuple;
 	struct nf_conntrack_tuple_hash *h = NULL;
@@ -1260,7 +1253,7 @@ static const size_t cta_min_exp[CTA_EXPECT_MAX] = {
 
 static int
 ctnetlink_get_expect(struct sock *ctnl, struct sk_buff *skb,
-		     struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+		     struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_tuple tuple;
 	struct nf_conntrack_expect *exp;
@@ -1273,17 +1266,12 @@ ctnetlink_get_expect(struct sock *ctnl, struct sk_buff *skb,
 		return -EINVAL;
 
 	if (nlh->nlmsg_flags & NLM_F_DUMP) {
-		u32 rlen;
-
-		if ((*errp = netlink_dump_start(ctnl, skb, nlh,
-						ctnetlink_exp_dump_table,
-						ctnetlink_done)) != 0)
-			return -EINVAL;
-		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
-		if (rlen > skb->len)
-			rlen = skb->len;
-		skb_pull(skb, rlen);
-		return 0;
+		err = netlink_dump_start(ctnl, skb, nlh,
+					 ctnetlink_exp_dump_table,
+					 ctnetlink_done);
+		if (err == 0)
+			err = -EINTR;
+		return err;
 	}
 
 	if (cda[CTA_EXPECT_MASTER-1])
@@ -1330,7 +1318,7 @@ out:
 
 static int
 ctnetlink_del_expect(struct sock *ctnl, struct sk_buff *skb,
-		     struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+		     struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_expect *exp, *tmp;
 	struct nf_conntrack_tuple tuple;
@@ -1464,7 +1452,7 @@ out:
 
 static int
 ctnetlink_new_expect(struct sock *ctnl, struct sk_buff *skb,
-		     struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+		     struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_tuple tuple;
 	struct nf_conntrack_expect *exp;
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index dec36abdf94..c37ed0156b0 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -195,17 +195,14 @@ int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags)
 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
 
 /* Process one complete nfnetlink message. */
-static int nfnetlink_rcv_msg(struct sk_buff *skb,
-				    struct nlmsghdr *nlh, int *errp)
+static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct nfnl_callback *nc;
 	struct nfnetlink_subsystem *ss;
-	int type, err = 0;
+	int type, err;
 
-	if (security_netlink_recv(skb, CAP_NET_ADMIN)) {
-		*errp = -EPERM;
-		return -1;
-	}
+	if (security_netlink_recv(skb, CAP_NET_ADMIN))
+		return -EPERM;
 
 	/* Only requests are handled by kernel now. */
 	if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
@@ -227,12 +224,12 @@ static int nfnetlink_rcv_msg(struct sk_buff *skb,
 		ss = nfnetlink_get_subsys(type);
 		if (!ss)
 #endif
-			goto err_inval;
+			return -EINVAL;
 	}
 
 	nc = nfnetlink_find_client(type, ss);
 	if (!nc)
-		goto err_inval;
+		return -EINVAL;
 
 	{
 		u_int16_t attr_count =
@@ -243,16 +240,9 @@ static int nfnetlink_rcv_msg(struct sk_buff *skb,
 
 		err = nfnetlink_check_attributes(ss, nlh, cda);
 		if (err < 0)
-			goto err_inval;
-
-		err = nc->call(nfnl, skb, nlh, cda, errp);
-		*errp = err;
-		return err;
+			return err;
+		return nc->call(nfnl, skb, nlh, cda);
 	}
-
-err_inval:
-	*errp = -EINVAL;
-	return -1;
 }
 
 static void nfnetlink_rcv(struct sock *sk, int len)
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index 9709f94787f..b174aadd73e 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -759,7 +759,7 @@ static struct notifier_block nfulnl_rtnl_notifier = {
 
 static int
 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
-		  struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
+		  struct nlmsghdr *nlh, struct nfattr *nfqa[])
 {
 	return -ENOTSUPP;
 }
@@ -797,7 +797,7 @@ static const int nfula_cfg_min[NFULA_CFG_MAX] = {
 
 static int
 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
-		   struct nlmsghdr *nlh, struct nfattr *nfula[], int *errp)
+		   struct nlmsghdr *nlh, struct nfattr *nfula[])
 {
 	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 	u_int16_t group_num = ntohs(nfmsg->res_id);
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index b6585caa431..9aefb1c9bfa 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -783,7 +783,7 @@ static const int nfqa_verdict_min[NFQA_MAX] = {
 
 static int
 nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
-		   struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
+		   struct nlmsghdr *nlh, struct nfattr *nfqa[])
 {
 	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 	u_int16_t queue_num = ntohs(nfmsg->res_id);
@@ -848,7 +848,7 @@ err_out_put:
 
 static int
 nfqnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
-		  struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
+		  struct nlmsghdr *nlh, struct nfattr *nfqa[])
 {
 	return -ENOTSUPP;
 }
@@ -865,7 +865,7 @@ static struct nf_queue_handler nfqh = {
 
 static int
 nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
-		  struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
+		  struct nlmsghdr *nlh, struct nfattr *nfqa[])
 {
 	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 	u_int16_t queue_num = ntohs(nfmsg->res_id);