From nobody Thu Apr 2 07:24:26 2026 Received: from out-170.mta0.migadu.com (out-170.mta0.migadu.com [91.218.175.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2925C37F8A2 for ; Mon, 30 Mar 2026 05:33:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.170 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774848800; cv=none; b=EDh7rPbyzMNu9+Zqba+cNzUXMrhc8RYQKnQ5KQwH2nIKvxoZePNPW9Ce+5N+X9x3P95WsaGwYxIG6gMJAauGL2Nn6yqWLzvvcufluHaxB2yKhNdIo+Sl/L1UvBTlz/W9SIhv/Zjdpokgr5UrS5LHkiZAJOCnz43mwRkh6aE2qoQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774848800; c=relaxed/simple; bh=ys1LYOCxjkmlSm/3bTmNwB+Od2iFUJqldBEHdfCjAvA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UycSwdFfIcG2oIi4hcPhbiyIsXLWEAOZWkWybjDxtUG4dJBXk0nFiXATe3yv2vyKrap5V39pys0fe3+oQy8hJTzb89k9ajwylpPhFQEy5QDCjEF/tauGTaQdzFuyR76WuPnovB/f4BeOESqFWiZIj4sTCR3O95v4tA4gQUCmC6E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=CNISR1mK; arc=none smtp.client-ip=91.218.175.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="CNISR1mK" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1774848797; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=boc++GcyEtCsXLwFDSOaXQkpg4hTrQfawgcm43IUzP4=; b=CNISR1mKkdqZpzbgNYGmieVr10FJ+jWg4Rykc9UriXS3mNpH7S+2QCY/7wCRKAYgx1rRMM 8TBrLN20kOXojG8oE4+rxbW1IeoLDz5fErFiFggOQLa64R/d4kXm82Wftx9K4Tc19HlcHY zxmpMAkJu0DkScaWFYISX0xYJx4r9Hs= From: Gang Yan To: mptcp@lists.linux.dev Cc: pabeni@redhat.com, Gang Yan , Geliang Tang Subject: [PATCH mptcp-net v4 2/5] mptcp: fix the stall problems using backlog_queue Date: Mon, 30 Mar 2026 13:32:57 +0800 Message-ID: <20260330053300.15717-3-gang.yan@linux.dev> In-Reply-To: <20260330053300.15717-1-gang.yan@linux.dev> References: <20260330053300.15717-1-gang.yan@linux.dev> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" From: Gang Yan The original condition would stop moving skbs or spooling backlog even when the receive queue is empty, leading to receive stall. Modify the condition in __mptcp_move_skbs() and mptcp_can_spool_backlog() to only treat rcvbuf as full when: sk_rmem_alloc_get(sk) > sk->sk_rcvbuf && !skb_queue_empty(&sk->sk_receive= _queue) This ensures the backlog can still be moved to the receive queue when the queue is empty, avoiding stall problems. Fixes: 6228efe0cc01 ("mptcp: leverage the backlog for RX packet processing") Co-developed-by: Geliang Tang Signed-off-by: Geliang Tang Signed-off-by: Gang Yan --- net/mptcp/protocol.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 03eaa92badd5..01d04cbea53d 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2197,6 +2197,12 @@ static void mptcp_rcv_space_adjust(struct mptcp_sock= *msk, int copied) msk->rcvq_space.time =3D mstamp; } =20 +static bool mptcp_can_dequeue_from_backlog(struct sock *sk) +{ + return sk_rmem_alloc_get(sk) <=3D sk->sk_rcvbuf || + skb_queue_empty(&sk->sk_receive_queue); +} + static bool __mptcp_move_skbs(struct sock *sk, struct list_head *skbs, u32= *delta) { struct sk_buff *skb =3D list_first_entry(skbs, struct sk_buff, list); @@ -2206,7 +2212,7 @@ static bool __mptcp_move_skbs(struct sock *sk, struct= list_head *skbs, u32 *delt *delta =3D 0; while (1) { /* If the msk recvbuf is full stop, don't drop */ - if (sk_rmem_alloc_get(sk) > sk->sk_rcvbuf) + if (!mptcp_can_dequeue_from_backlog(sk)) break; =20 prefetch(skb->next); @@ -2261,7 +2267,7 @@ static bool mptcp_can_spool_backlog(struct sock *sk, = struct list_head *skbs) =20 /* Don't spool the backlog if the rcvbuf is full. */ if (RB_EMPTY_ROOT(&msk->backlog_queue) || - sk_rmem_alloc_get(sk) > sk->sk_rcvbuf) + !mptcp_can_dequeue_from_backlog(sk)) return false; =20 INIT_LIST_HEAD(skbs); --=20 2.43.0