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[79.18.148.79]) by smtp.gmail.com with ESMTPSA id f18sm726664ejx.23.2021.07.27.02.58.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Jul 2021 02:58:05 -0700 (PDT) Date: Tue, 27 Jul 2021 11:58:03 +0200 From: Stefano Garzarella To: Arseny Krasnov Cc: Stefan Hajnoczi , "Michael S. Tsirkin" , Jason Wang , "David S. Miller" , Jakub Kicinski , Colin Ian King , Andra Paraschiv , Norbert Slusarek , "kvm@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "oxffffaa@gmail.com" Subject: Re: [MASSMAIL KLMS] Re: [RFC PATCH v1 0/7] virtio/vsock: introduce MSG_EOR flag for SEQPACKET Message-ID: <20210727095803.s26subp3pgclqzvi@steredhat> References: <20210726163137.2589102-1-arseny.krasnov@kaspersky.com> <20210727075948.yl4w3foqa6rp4obg@steredhat> <2df68589-96b9-abd4-ad1c-e25918b908a9@kaspersky.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <2df68589-96b9-abd4-ad1c-e25918b908a9@kaspersky.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 27, 2021 at 12:34:36PM +0300, Arseny Krasnov wrote: > >On 27.07.2021 10:59, Stefano Garzarella wrote: >> Caution: This is an external email. Be cautious while opening links or attachments. >> >> >> >> On Mon, Jul 26, 2021 at 07:31:33PM +0300, Arseny Krasnov wrote: >>> This patchset implements support of MSG_EOR bit for SEQPACKET >>> AF_VSOCK sockets over virtio transport. >>> Idea is to distinguish concepts of 'messages' and 'records'. >>> Message is result of sending calls: 'write()', 'send()', 'sendmsg()' >>> etc. It has fixed maximum length, and it bounds are visible using >>> return from receive calls: 'read()', 'recv()', 'recvmsg()' etc. >>> Current implementation based on message definition above. >>> Record has unlimited length, it consists of multiple message, >>> and bounds of record are visible via MSG_EOR flag returned from >>> 'recvmsg()' call. Sender passes MSG_EOR to sending system call and >>> receiver will see MSG_EOR when corresponding message will be processed. >>> To support MSG_EOR new bit was added along with existing >>> 'VIRTIO_VSOCK_SEQ_EOR': 'VIRTIO_VSOCK_SEQ_EOM'(end-of-message) - now it >>> works in the same way as 'VIRTIO_VSOCK_SEQ_EOR'. But 'VIRTIO_VSOCK_SEQ_EOR' >>> is used to mark 'MSG_EOR' bit passed from userspace. >> At this point it's probably better to rename the old flag, so we stay >> compatible. >> >> What happens if one of the two peers does not support MSG_EOR handling, >> while the other does? >> >> I'll do a closer review in the next few days. >Thank You, also i think MSG_EOR support must be described in spec Yep, sure! What do you think about the concerns above? Stefano