[NETLINK]: Directly return -EINTR from netlink_dump_start()

Now that all users of netlink_dump_start() use netlink_run_queue()
to process the receive queue, it is possible to return -EINTR from
netlink_dump_start() directly, therefore simplying the callers.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/rtnetlink.c

@@ -859,7 +859,6 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	int min_len;
 	int family;
 	int type;
-	int err;
 
 	type = nlh->nlmsg_type;
 	if (type > RTM_MAX)
@@ -888,10 +887,7 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		if (dumpit == NULL)
 			return -EINVAL;
 
-		err = netlink_dump_start(rtnl, skb, nlh, dumpit, NULL);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(rtnl, skb, nlh, dumpit, NULL);
 	}
 
 	memset(rta_buf, 0, (rtattr_max * sizeof(struct rtattr *)));

net/ipv4/inet_diag.c

@@ -818,8 +818,6 @@ static int inet_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		return -ENOENT;
 
 	if (nlh->nlmsg_flags & NLM_F_DUMP) {
-		int err;
-
 		if (nlmsg_attrlen(nlh, hdrlen)) {
 			struct nlattr *attr;
 
@@ -831,11 +829,8 @@ static int inet_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 				return -EINVAL;
 		}
 
-		err = netlink_dump_start(idiagnl, skb, nlh,
-					 inet_diag_dump, NULL);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(idiagnl, skb, nlh,
+					  inet_diag_dump, NULL);
 	}
 
 	return inet_diag_get_exact(skb, nlh);

net/netfilter/nf_conntrack_netlink.c

@@ -724,11 +724,8 @@ ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb,
 		if (NFNL_MSG_TYPE(nlh->nlmsg_type) == IPCTNL_MSG_CT_GET_CTRZERO)
 			return -ENOTSUPP;
 #endif
-		err = netlink_dump_start(ctnl, skb, nlh, ctnetlink_dump_table,
-					 ctnetlink_done);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(ctnl, skb, nlh, ctnetlink_dump_table,
+					  ctnetlink_done);
 	}
 
 	if (nfattr_bad_size(cda, CTA_MAX, cta_min))
@@ -1266,12 +1263,9 @@ ctnetlink_get_expect(struct sock *ctnl, struct sk_buff *skb,
 		return -EINVAL;
 
 	if (nlh->nlmsg_flags & NLM_F_DUMP) {
-		err = netlink_dump_start(ctnl, skb, nlh,
-					 ctnetlink_exp_dump_table,
-					 ctnetlink_done);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(ctnl, skb, nlh,
+					  ctnetlink_exp_dump_table,
+					  ctnetlink_done);
 	}
 
 	if (cda[CTA_EXPECT_MASTER-1])

net/netlink/af_netlink.c

@@ -1426,7 +1426,12 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 
 	netlink_dump(sk);
 	sock_put(sk);
-	return 0;
+
+	/* We successfully started a dump, by returning -EINTR we
+	 * signal the queue mangement to interrupt processing of
+	 * any netlink messages so userspace gets a chance to read
+	 * the results. */
+	return -EINTR;
 }
 
 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)

net/netlink/genetlink.c

@@ -323,11 +323,8 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		if (ops->dumpit == NULL)
 			return -EOPNOTSUPP;
 
-		err = netlink_dump_start(genl_sock, skb, nlh,
-					 ops->dumpit, ops->done);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(genl_sock, skb, nlh,
+					  ops->dumpit, ops->done);
 	}
 
 	if (ops->doit == NULL)

net/xfrm/xfrm_user.c

@@ -1856,7 +1856,7 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct rtattr *xfrma[XFRMA_MAX];
 	struct xfrm_link *link;
-	int type, min_len, err;
+	int type, min_len;
 
 	type = nlh->nlmsg_type;
 	if (type > XFRM_MSG_MAX)
@@ -1875,10 +1875,7 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		if (link->dump == NULL)
 			return -EINVAL;
 
-		err = netlink_dump_start(xfrm_nl, skb, nlh, link->dump, NULL);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(xfrm_nl, skb, nlh, link->dump, NULL);
 	}
 
 	memset(xfrma, 0, sizeof(xfrma));