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Message-ID: <4d532e35-c03c-fbf6-0744-9397e269750d@sberdevices.ru>
Date:   Tue, 27 Jun 2023 07:49:00 +0300
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Subject: Re: [RFC PATCH v4 07/17] vsock: read from socket's error queue
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To:     Stefano Garzarella <sgarzare@redhat.com>
CC:     Stefan Hajnoczi <stefanha@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Bobby Eshleman <bobby.eshleman@bytedance.com>,
        <kvm@vger.kernel.org>, <virtualization@lists.linux-foundation.org>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <kernel@sberdevices.ru>, <oxffffaa@gmail.com>
References: <20230603204939.1598818-1-AVKrasnov@sberdevices.ru>
 <20230603204939.1598818-8-AVKrasnov@sberdevices.ru>
 <sq5jlfhhlj347uapazqnotc5rakzdvj33ruzqwxdjsfx275m5r@dxujwphcffkl>
From:   Arseniy Krasnov <avkrasnov@sberdevices.ru>
In-Reply-To: <sq5jlfhhlj347uapazqnotc5rakzdvj33ruzqwxdjsfx275m5r@dxujwphcffkl>
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On 26.06.2023 19:08, Stefano Garzarella wrote:
> On Sat, Jun 03, 2023 at 11:49:29PM +0300, Arseniy Krasnov wrote:
>> This adds handling of MSG_ERRQUEUE input flag in receive call. This flag
>> is used to read socket's error queue instead of data queue. Possible
>> scenario of error queue usage is receiving completions for transmission
>> with MSG_ZEROCOPY flag.
>>
>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>> ---
>> include/linux/socket.h   | 1 +
>> net/vmw_vsock/af_vsock.c | 5 +++++
>> 2 files changed, 6 insertions(+)
>>
>> diff --git a/include/linux/socket.h b/include/linux/socket.h
>> index bd1cc3238851..d79efd026880 100644
>> --- a/include/linux/socket.h
>> +++ b/include/linux/socket.h
>> @@ -382,6 +382,7 @@ struct ucred {
>> #define SOL_MPTCP    284
>> #define SOL_MCTP    285
>> #define SOL_SMC        286
>> +#define SOL_VSOCK    287
> 
> Maybe this change should go in another patch where we describe that
> we need to support setsockopt()

Ok, You mean patch which handles SO_ZEROCOPY option in af_vsock.c as Bobby suggested? No
problem, but in this case there will be no user for this define there - this option
(SO_ZEROCOPY) uses SOL_SOCKET level, not SOL_VSOCK.

Thanks, Arseniy

> 
>>
>> /* IPX options */
>> #define IPX_TYPE    1
>> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>> index 45fd20c4ed50..07803d9fbf6d 100644
>> --- a/net/vmw_vsock/af_vsock.c
>> +++ b/net/vmw_vsock/af_vsock.c
>> @@ -110,6 +110,7 @@
>> #include <linux/workqueue.h>
>> #include <net/sock.h>
>> #include <net/af_vsock.h>
>> +#include <linux/errqueue.h>
>>
>> static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr);
>> static void vsock_sk_destruct(struct sock *sk);
>> @@ -2135,6 +2136,10 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
>>     int err;
>>
>>     sk = sock->sk;
>> +
>> +    if (unlikely(flags & MSG_ERRQUEUE))
>> +        return sock_recv_errqueue(sk, msg, len, SOL_VSOCK, 0);
>> +
>>     vsk = vsock_sk(sk);
>>     err = 0;
>>
>> -- 
>> 2.25.1
>>
>