neighbour: Make neigh_valid_get_req() return ndmsg.

neigh_get() passes 4 local variable pointers to neigh_valid_get_req().

If it returns a pointer of struct ndmsg, we do not need to pass two
of them.

Signed-off-by: Kuniyuki Iwashima <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: q2ven

net/core/neighbour.c

@@ -2910,10 +2910,9 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 	return err;
 }
 
-static int neigh_valid_get_req(const struct nlmsghdr *nlh,
-			       struct neigh_table **tbl,
-			       void **dst, int *dev_idx, u8 *ndm_flags,
-			       struct netlink_ext_ack *extack)
+static struct ndmsg *neigh_valid_get_req(const struct nlmsghdr *nlh,
+					 struct neigh_table **tbl, void **dst,
+					 struct netlink_ext_ack *extack)
 {
 	struct nlattr *tb[NDA_MAX + 1];
 	struct ndmsg *ndm;
@@ -2922,31 +2921,29 @@ static int neigh_valid_get_req(const struct nlmsghdr *nlh,
 	ndm = nlmsg_payload(nlh, sizeof(*ndm));
 	if (!ndm) {
 		NL_SET_ERR_MSG(extack, "Invalid header for neighbor get request");
-		return -EINVAL;
+		return ERR_PTR(-EINVAL);
 	}
 
 	if (ndm->ndm_pad1  || ndm->ndm_pad2  || ndm->ndm_state ||
 	    ndm->ndm_type) {
 		NL_SET_ERR_MSG(extack, "Invalid values in header for neighbor get request");
-		return -EINVAL;
+		return ERR_PTR(-EINVAL);
 	}
 
 	if (ndm->ndm_flags & ~NTF_PROXY) {
 		NL_SET_ERR_MSG(extack, "Invalid flags in header for neighbor get request");
-		return -EINVAL;
+		return ERR_PTR(-EINVAL);
 	}
 
 	err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct ndmsg), tb,
 					    NDA_MAX, nda_policy, extack);
 	if (err < 0)
-		return err;
+		return ERR_PTR(err);
 
-	*ndm_flags = ndm->ndm_flags;
-	*dev_idx = ndm->ndm_ifindex;
 	*tbl = neigh_find_table(ndm->ndm_family);
-	if (*tbl == NULL) {
+	if (!*tbl) {
 		NL_SET_ERR_MSG(extack, "Unsupported family in header for neighbor get request");
-		return -EAFNOSUPPORT;
+		return ERR_PTR(-EAFNOSUPPORT);
 	}
 
 	for (i = 0; i <= NDA_MAX; ++i) {
@@ -2957,17 +2954,17 @@ static int neigh_valid_get_req(const struct nlmsghdr *nlh,
 		case NDA_DST:
 			if (nla_len(tb[i]) != (int)(*tbl)->key_len) {
 				NL_SET_ERR_MSG(extack, "Invalid network address in neighbor get request");
-				return -EINVAL;
+				return ERR_PTR(-EINVAL);
 			}
 			*dst = nla_data(tb[i]);
 			break;
 		default:
 			NL_SET_ERR_MSG(extack, "Unsupported attribute in neighbor get request");
-			return -EINVAL;
+			return ERR_PTR(-EINVAL);
 		}
 	}
 
-	return 0;
+	return ndm;
 }
 
 static inline size_t neigh_nlmsg_size(void)
@@ -3038,18 +3035,16 @@ static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 	struct net_device *dev = NULL;
 	struct neigh_table *tbl = NULL;
 	struct neighbour *neigh;
+	struct ndmsg *ndm;
 	void *dst = NULL;
-	u8 ndm_flags = 0;
-	int dev_idx = 0;
 	int err;
 
-	err = neigh_valid_get_req(nlh, &tbl, &dst, &dev_idx, &ndm_flags,
-				  extack);
-	if (err < 0)
-		return err;
+	ndm = neigh_valid_get_req(nlh, &tbl, &dst, extack);
+	if (IS_ERR(ndm))
+		return PTR_ERR(ndm);
 
-	if (dev_idx) {
-		dev = __dev_get_by_index(net, dev_idx);
+	if (ndm->ndm_ifindex) {
+		dev = __dev_get_by_index(net, ndm->ndm_ifindex);
 		if (!dev) {
 			NL_SET_ERR_MSG(extack, "Unknown device ifindex");
 			return -ENODEV;
@@ -3061,7 +3056,7 @@ static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 		return -EINVAL;
 	}
 
-	if (ndm_flags & NTF_PROXY) {
+	if (ndm->ndm_flags & NTF_PROXY) {
 		struct pneigh_entry *pn;
 
 		pn = pneigh_lookup(tbl, net, dst, dev, 0);