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[79.34.249.199]) by smtp.gmail.com with ESMTPSA id q25sm1506681edt.51.2021.04.22.01.46.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Apr 2021 01:46:40 -0700 (PDT) Date: Thu, 22 Apr 2021 10:46:38 +0200 From: Stefano Garzarella To: Arseny Krasnov Cc: Stefan Hajnoczi , "Michael S. Tsirkin" , Jason Wang , "David S. Miller" , Jakub Kicinski , Jorgen Hansen , Colin Ian King , Andra Paraschiv , Norbert Slusarek , Alexander Popov , "kvm@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "stsp2@yandex.ru" , "oxffffaa@gmail.com" Subject: Re: [RFC PATCH v8 00/19] virtio/vsock: introduce SOCK_SEQPACKET support Message-ID: <20210422084638.bvblk33b4oi6cec6@steredhat> References: <20210413123954.3396314-1-arseny.krasnov@kaspersky.com> <20210421095213.25hnfi2th7gzyzt2@steredhat> <2c3d0749-0f41-e064-0153-b6130268add2@kaspersky.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <2c3d0749-0f41-e064-0153-b6130268add2@kaspersky.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 21, 2021 at 06:06:28PM +0300, Arseny Krasnov wrote: >On 21.04.2021 12:52, Stefano Garzarella wrote: >> On Tue, Apr 13, 2021 at 03:39:51PM +0300, Arseny Krasnov wrote: >>> v7 -> v8: >>> General changelog: >>> - whole idea is simplified: channel now considered reliable, >>> so SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id' were removed. >>> Only thing that is used to mark end of message is bit in >>> 'flags' field of packet header: VIRTIO_VSOCK_SEQ_EOR. Packet >>> with such bit set to 1 means, that this is last packet of >>> message. >>> >>> - POSIX MSG_EOR support is removed, as there is no exact >>> description how it works. >> It would be nice to support it, I'll try to see if I can find anything. >> >> I just reviewed the series. I think the most important things to fix are >> the `seqpacket_allow` stored in the struct virtio_transport that is >> wrong IMHO, and use cpu_to_le32()/le32_to_cpu() to access the flags. > >Thank You, i'll prepare next version. Main question is: does this >approach(no SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id') considered >good? In this case it will be easier to prepare final version, because >is smaller and more simple than previous logic. Also patch to spec >will be smaller. Yes, it's definitely much better than before. The only problem I see is that we add some overhead per fragment (header). We could solve that with the mergeable buffers that Jiang is considering for DGRAM. If we have that support, I think we could reuse it here as well, but it might be a next step. Thanks, Stefano