From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 88B79C8E8 for ; Sun, 8 Oct 2023 14:05:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BGTR/sct" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 39BD2C433C7; Sun, 8 Oct 2023 14:05:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696773913; bh=r+kHAtGuKG0Uq8FmFEjHIdQQVxFfRqk1vuA/7M3mQvA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=BGTR/sct4mZiXE8+tuAcAGDLWGG8o8tNQGeXVmnrU0pS3d5+ojmL7C75628Y7MaJ7 XRrhj7T/fqCZw1SVexSskT1zTZ2mejcdXWgwShznT/LmxBPY2GO4Y0Wzp9LW16x6BF LO2P6zG+aLjkoTrrW9cuj4du3nkNAYzNzPTie25MtIJWivOuNNiYdTxIlJX/Ixo1NQ klhS6Dpz77jOc9GkKC6LOyJzz7V9sMTAglMRsGCOw4xXyg/jEabHlDIMXb9cFliiBT AgoyHESokZRV9xSK/+yjXgg/YD/4OhRQyFEmmSCipKz0CCQFVIryTAoHKqvyI6RITP 8M/M628ijf8og== Message-ID: Date: Sun, 8 Oct 2023 16:05:10 +0200 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mptcp-next v11 1/4] mptcp: set next subflow to msk->first Content-Language: en-GB, fr-BE To: Geliang Tang , Paolo Abeni Cc: mptcp@lists.linux.dev References: <6a31565e01d3474be56bdf62c54d0c20c065c65c.1696760702.git.geliang.tang@suse.com> <6c266459-dbba-4bda-b868-b5bcdaf351b0@kernel.org> <20231008123313.GA8315@localhost> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Geliang, On 08/10/2023 14:33, Geliang Tang wrote: > On Sun, Oct 08, 2023 at 01:11:32PM +0200, Matthieu Baerts wrote: >> Hi Geliang, >> >> +cc Paolo >> >> On 08/10/2023 12:27, Geliang Tang wrote: >>> When closing the msk->first socket in __mptcp_close_ssk(), the original >>> behaviour is to reset this socket. But if there's another subflow available >>> in this case, it's better to set the first available subflow to msk->first, >>> instead of resetting the msk->first. >> >> I don't think we want to do that. If I remember well, we want to keep >> having 'msk->first' pointing to the initial subflow for various reasons >> (I don't remember exactly). >> >> I think what we want to do is not to reset the initial subflow if there >> are other subflows still available and we don't want to set it to 'NULL' >> in such case. > > Is it like this: > > if (ssk == msk->first && !msk->pm.subflows) > WRITE_ONCE(msk->first, NULL); No, we cannot set it to NULL nor release it but we should avoid the "reset" being sent. I don't have access to the code for the moment but by looking at your patch, I would say you should not modify 'dispose_it' nor 'msk->first' but maybe check if you can avoid calling 'mptcp_subflow_ctx_reset()' if '!dispose_it', maybe by checking something like 'list_is_singular(&msk->conn_list)'? (I think you should avoid looking at the PM structure here). Please tell me if it is not clear. Cheers, Matt -- Tessares | Belgium | Hybrid Access Solutions www.tessares.net