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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , =?UTF-8?q?Daniel=20Gr=C3=B6ber?= , Antonio Quartulli , linux-kernel@vger.kernel.org Subject: [RFC net-next v2 01/18] lwtunnel: track callback dispatch separately from return value Date: Sat, 24 Oct 2026 11:25:11 +0200 Message-ID: <20261024092532.172005-2-ralf@mandelbit.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20261024092532.172005-1-ralf@mandelbit.com> References: <20261024092532.172005-1-ralf@mandelbit.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 4jBZJB5ZRzzFphR LWT used -EOPNOTSUPP both as its missing-callback sentinel and as a valid callback error. Track whether an operation was invoked separately so callbacks can return meaningful errors without triggering the no-operation skb cleanup path. Signed-off-by: Ralf Lici --- New patch in RFC v2. net/core/lwtunnel.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c index 8223c44f10c8..db21b9ff6f86 100644 --- a/net/core/lwtunnel.c +++ b/net/core/lwtunnel.c @@ -322,6 +322,7 @@ int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb) { const struct lwtunnel_encap_ops *ops; struct lwtunnel_state *lwtstate; + bool called_cb = false; struct dst_entry *dst; int ret; @@ -353,13 +354,14 @@ int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb) if (likely(ops && ops->output)) { /* Encap pushes outer headers over the metadata; drop it. */ skb_metadata_clear(skb); + called_cb = true; dev_xmit_recursion_inc(); ret = ops->output(net, sk, skb); dev_xmit_recursion_dec(); } rcu_read_unlock(); - if (ret == -EOPNOTSUPP) + if (unlikely(!called_cb)) goto drop; goto out; @@ -377,6 +379,7 @@ int lwtunnel_xmit(struct sk_buff *skb) { const struct lwtunnel_encap_ops *ops; struct lwtunnel_state *lwtstate; + bool called_cb = false; struct dst_entry *dst; int ret; @@ -409,13 +412,14 @@ int lwtunnel_xmit(struct sk_buff *skb) if (likely(ops && ops->xmit)) { /* Encap pushes outer headers over the metadata; drop it. */ skb_metadata_clear(skb); + called_cb = true; dev_xmit_recursion_inc(); ret = ops->xmit(skb); dev_xmit_recursion_dec(); } rcu_read_unlock(); - if (ret == -EOPNOTSUPP) + if (unlikely(!called_cb)) goto drop; goto out; @@ -433,6 +437,7 @@ int lwtunnel_input(struct sk_buff *skb) { const struct lwtunnel_encap_ops *ops; struct lwtunnel_state *lwtstate; + bool called_cb = false; struct dst_entry *dst; int ret; @@ -462,13 +467,14 @@ int lwtunnel_input(struct sk_buff *skb) if (likely(ops && ops->input)) { /* Encap pushes outer headers over the metadata; drop it. */ skb_metadata_clear(skb); + called_cb = true; dev_xmit_recursion_inc(); ret = ops->input(skb); dev_xmit_recursion_dec(); } rcu_read_unlock(); - if (ret == -EOPNOTSUPP) + if (unlikely(!called_cb)) goto drop; return ret; -- 2.55.0