[PATCH mptcp-next 0/2] fixes for "mptcp: receive path improvement" v3

[PATCH mptcp-next 0/2] fixes for "mptcp: receive path improvement" v3

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

Try to fix errors reported by CI.

Based-on: <cover.1758296923.git.pabeni@redhat.com>

Geliang Tang (2):
  Squash to "mptcp: factor out a basic skb coalesce helper"
  Squash to "mptcp: leverage the sk backlog for RX packet processing."

 net/mptcp/protocol.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

-- 
2.48.1

[PATCH mptcp-next 1/2] Squash to "mptcp: factor out a basic skb coalesce helper"

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

Fix the return value of __mptcp_try_coalesce.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/protocol.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 7db5adb43d41..d114ed1bd61a 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -142,23 +142,23 @@ static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
 	__kfree_skb(skb);
 }
 
-static int __mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
-				struct sk_buff *from, bool *fragstolen)
+static bool __mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
+				 struct sk_buff *from, bool *fragstolen,
+				 int *delta)
 {
 	int limit = READ_ONCE(sk->sk_rcvbuf);
-	int delta;
 
 	if (unlikely(MPTCP_SKB_CB(to)->cant_coalesce) ||
 	    MPTCP_SKB_CB(from)->offset ||
 	    ((to->len + from->len) > (limit >> 3)) ||
-	    !skb_try_coalesce(to, from, fragstolen, &delta))
-		return 0;
+	    !skb_try_coalesce(to, from, fragstolen, delta))
+		return false;
 
 	pr_debug("colesced seq %llx into %llx new len %d new end seq %llx\n",
 		 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
 		 to->len, MPTCP_SKB_CB(from)->end_seq);
 	MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
-	return delta;
+	return true;
 }
 
 static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
@@ -167,8 +167,7 @@ static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
 	bool fragstolen;
 	int delta;
 
-	delta = __mptcp_try_coalesce(sk, to, from, &fragstolen);
-	if (!delta)
+	if (!__mptcp_try_coalesce(sk, to, from, &fragstolen, &delta))
 		return false;
 
 	/* note the fwd memory can reach a negative value after accounting
-- 
2.48.1

[PATCH mptcp-next 2/2] Squash to "mptcp: leverage the sk backlog for RX packet processing."

[Geliang Tang]

From: Geliang Tang <tanggeliang@kylinos.cn>

Use new __mptcp_try_coalesce.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/protocol.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index d114ed1bd61a..85dce66e12a3 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -377,8 +377,7 @@ static void __mptcp_add_backlog(struct sock *sk, struct sock *ssk,
 	int delta;
 
 	if (tail && MPTCP_SKB_CB(skb)->map_seq == MPTCP_SKB_CB(tail)->end_seq) {
-		delta = __mptcp_try_coalesce(sk, tail, skb, &fragstolen);
-		if (delta) {
+		if (__mptcp_try_coalesce(sk, tail, skb, &fragstolen, &delta)) {
 			sk->sk_backlog.len += delta;
 			kfree_skb_partial(skb, fragstolen);
 			return;
-- 
2.48.1

Re: [PATCH mptcp-next 0/2] fixes for "mptcp: receive path improvement" v3

[Matthieu Baerts]

Hi Geliang, Paolo,

On 20/09/2025 05:44, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> Try to fix errors reported by CI.

@Geliang: Thank you! The modifications make sense to me.

@Paolo: do you want to send the v4 series to netdev directly?

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

Re: [PATCH mptcp-next 0/2] fixes for "mptcp: receive path improvement" v3

[Paolo Abeni]

On 9/22/25 10:35 AM, Matthieu Baerts wrote:
> Hi Geliang, Paolo,
> 
> On 20/09/2025 05:44, Geliang Tang wrote:
>> From: Geliang Tang <tanggeliang@kylinos.cn>
>>
>> Try to fix errors reported by CI.
> 
> @Geliang: Thank you! The modifications make sense to me.
> 
> @Paolo: do you want to send the v4 series to netdev directly?

I also have some questions :)

Does this follow-up address the CI failures for good?

I think patch 1-3 could be merged and export and send to netdev. Patch
10/10 is possibly a little too invasive at this to enter 6.18 this late.
I *think* it could wait the next cycles (together with all the pre-req
and follow-up), but I'm ok to go ahead now, too. (But CI has to be happy
before sharing on netdev).

WDYT?

/P

Re: [PATCH mptcp-next 0/2] fixes for "mptcp: receive path improvement" v3

[Matthieu Baerts]

Hi Paolo,

On 22/09/2025 10:43, Paolo Abeni wrote:
> On 9/22/25 10:35 AM, Matthieu Baerts wrote:
>> Hi Geliang, Paolo,
>>
>> On 20/09/2025 05:44, Geliang Tang wrote:
>>> From: Geliang Tang <tanggeliang@kylinos.cn>
>>>
>>> Try to fix errors reported by CI.
>>
>> @Geliang: Thank you! The modifications make sense to me.
>>
>> @Paolo: do you want to send the v4 series to netdev directly?
> 
> I also have some questions :)
> 
> Does this follow-up address the CI failures for good?

When I sent my email, I noticed Patchew didn't process these patches. I
manually started the CI, it's in progress, but all the mptcp_connect*.sh
tests have passed!

https://github.com/multipath-tcp/mptcp_net-next/actions/runs/17909424668

> I think patch 1-3 could be merged and export and send to netdev. Patch
> 10/10 is possibly a little too invasive at this to enter 6.18 this late.
> I *think* it could wait the next cycles (together with all the pre-req
> and follow-up), but I'm ok to go ahead now, too. (But CI has to be happy
> before sharing on netdev).

Mmh, I would say: because the v6.18 is supposed to be the next LTS, and
syzkaller doesn't seem to complain, I *think* it might be worth it to be
more aligned with what TCP is doing, and send all patches to net-next.
(With or without the small changes suggested by Geliang, up to you, I'm
fine with or without them.)

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

Re: [PATCH mptcp-next 0/2] fixes for "mptcp: receive path improvement" v3

[MPTCP CI]

Hi Geliang,

Thank you for your modifications, that's great!

But sadly, our CI spotted some issues with it when trying to build it.

You can find more details there:

  https://github.com/multipath-tcp/mptcp_net-next/actions/runs/17909424670

Status: failure
Initiator: Matthieu Baerts (NGI0)
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/808fa7e15d01
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1004452

Feel free to reply to this email if you cannot access logs, if you need
some support to fix the error, if this doesn't seem to be caused by your
modifications or if the error is a false positive one.

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)

Re: [PATCH mptcp-next 0/2] fixes for "mptcp: receive path improvement" v3

[MPTCP CI]

Hi Geliang,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal: Unstable: 1 failed test(s): selftest_simult_flows 🔴
- KVM Validation: debug: Success! ✅
- KVM Validation: btf-normal (only bpftest_all): Success! ✅
- KVM Validation: btf-debug (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/17909424668

Initiator: Matthieu Baerts (NGI0)
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/808fa7e15d01
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1004452


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-normal

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)

Re: [PATCH mptcp-next 0/2] fixes for "mptcp: receive path improvement" v3

[MPTCP CI]

Hi Geliang,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal: Success! ✅
- KVM Validation: debug: Success! ✅
- KVM Validation: btf-normal (only bpftest_all): Success! ✅
- KVM Validation: btf-debug (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/17909424668

Initiator: Matthieu Baerts (NGI0)
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/808fa7e15d01
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1004452


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-normal

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)