net/sched: propagate tc_fill_tclass() error

Change tc_fill_tclass() to return -EMSGSIZE when skb is too small.

Change its caller to propagate this error (instead of -EINVAL)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260430023628.3216283-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index ed869a5ffc7377b7c19e66ae5fc9788e709488da..32ccd4672083aa19340520155aeba6d8b6ff546c 100644 (file)
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1987,15 +1987,16 @@ static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
 out_nlmsg_trim:
 nla_put_failure:
        nlmsg_trim(skb, b);
-       return -1;
+       return -EMSGSIZE;
 }
 
 static int tclass_notify(struct net *net, struct sk_buff *oskb,
                         struct nlmsghdr *n, struct Qdisc *q,
                         unsigned long cl, int event, struct netlink_ext_ack *extack)
 {
-       struct sk_buff *skb;
        u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
+       struct sk_buff *skb;
+       int ret;
 
        if (!rtnl_notify_needed(net, n->nlmsg_flags, RTNLGRP_TC))
                return 0;
@@ -2004,9 +2005,10 @@ static int tclass_notify(struct net *net, struct sk_buff *oskb,
        if (!skb)
                return -ENOBUFS;
 
-       if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, event, extack) < 0) {
+       ret = tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, event, extack);
+       if (ret < 0) {
                kfree_skb(skb);
-               return -EINVAL;
+               return ret;
        }
 
        return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
@@ -2017,17 +2019,19 @@ static int tclass_get_notify(struct net *net, struct sk_buff *oskb,
                             struct nlmsghdr *n, struct Qdisc *q,
                             unsigned long cl, struct netlink_ext_ack *extack)
 {
-       struct sk_buff *skb;
        u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
+       struct sk_buff *skb;
+       int ret;
 
        skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
        if (!skb)
                return -ENOBUFS;
 
-       if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, RTM_NEWTCLASS,
-                          extack) < 0) {
+       ret = tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
+                            RTM_NEWTCLASS, extack);
+       if (ret < 0) {
                kfree_skb(skb);
-               return -EINVAL;
+               return ret;
        }
 
        return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
@@ -2041,7 +2045,7 @@ static int tclass_del_notify(struct net *net,
                             struct netlink_ext_ack *extack)
 {
        u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
-       struct sk_buff *skb;
+       struct sk_buff *skb = NULL;
        int err = 0;
 
        if (!cops->delete)
@@ -2052,13 +2056,12 @@ static int tclass_del_notify(struct net *net,
                if (!skb)
                        return -ENOBUFS;
 
-               if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
-                                  RTM_DELTCLASS, extack) < 0) {
+               err = tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
+                                    RTM_DELTCLASS, extack);
+               if (err < 0) {
                        kfree_skb(skb);
-                       return -EINVAL;
+                       return err;
                }
-       } else {
-               skb = NULL;
        }
 
        err = cops->delete(q, cl, extack);