Re: [RFC PATCH v6 06/22] af_vsock: implement send logic for SEQPACKET

From: Arseny Krasnov <arseny.krasnov@kaspersky.com>
To: Stefano Garzarella <sgarzare@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Jorgen Hansen <jhansen@vmware.com>,
	Andra Paraschiv <andraprs@amazon.com>,
	Colin Ian King <colin.king@canonical.com>,
	Norbert Slusarek <nslusarek@gmx.net>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"virtualization@lists.linux-foundation.org" 
	<virtualization@lists.linux-foundation.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"stsp2@yandex.ru" <stsp2@yandex.ru>,
	"oxffffaa@gmail.com" <oxffffaa@gmail.com>
Subject: Re: [RFC PATCH v6 06/22] af_vsock: implement send logic for SEQPACKET
Date: Mon, 15 Mar 2021 10:49:51 +0300	[thread overview]
Message-ID: <47b8a0a6-652e-8168-43c0-79dba382c4d6@kaspersky.com> (raw)
In-Reply-To: <20210312151027.kamodty37ftspkmc@steredhat>


On 12.03.2021 18:10, Stefano Garzarella wrote:
> On Sun, Mar 07, 2021 at 09:00:26PM +0300, Arseny Krasnov wrote:
>> This adds some logic to current stream enqueue function for SEQPACKET
>> support:
>> 1) Use transport's seqpacket enqueue callback.
>> 2) Return value from enqueue function is whole record length or error
>>   for SOCK_SEQPACKET.
>>
>> Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>> ---
>> include/net/af_vsock.h   |  2 ++
>> net/vmw_vsock/af_vsock.c | 22 ++++++++++++++++------
>> 2 files changed, 18 insertions(+), 6 deletions(-)
>>
>> diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
>> index a8c4039e40cf..aed306292ab3 100644
>> --- a/include/net/af_vsock.h
>> +++ b/include/net/af_vsock.h
>> @@ -139,6 +139,8 @@ struct vsock_transport {
>> 	size_t (*seqpacket_seq_get_len)(struct vsock_sock *vsk);
>> 	int (*seqpacket_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
>> 				 int flags, bool *msg_ready);
>> +	int (*seqpacket_enqueue)(struct vsock_sock *vsk, struct msghdr *msg,
>> +				 int flags, size_t len);
>>
>> 	/* Notification. */
>> 	int (*notify_poll_in)(struct vsock_sock *, size_t, bool *);
>> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>> index 5bf64a3e678a..a031f165494d 100644
>> --- a/net/vmw_vsock/af_vsock.c
>> +++ b/net/vmw_vsock/af_vsock.c
>> @@ -1830,9 +1830,14 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
>> 		 * responsibility to check how many bytes we were able to send.
>> 		 */
>>
>> -		written = transport->stream_enqueue(
>> -				vsk, msg,
>> -				len - total_written);
>> +		if (sk->sk_type == SOCK_SEQPACKET) {
>> +			written = transport->seqpacket_enqueue(vsk,
>> +						msg, msg->msg_flags,
> I think we can avoid to pass 'msg->msg_flags', since the transport can 
> access it through the 'msg' pointer, right?
Ack
>
>> +						len - total_written);
>> +		} else {
>> +			written = transport->stream_enqueue(vsk,
>> +					msg, len - total_written);
>> +		}
>> 		if (written < 0) {
>> 			err = -ENOMEM;
>> 			goto out_err;
>> @@ -1844,12 +1849,17 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
>> 				vsk, written, &send_data);
>> 		if (err < 0)
>> 			goto out_err;
>> -
>> 	}
>>
>> out_err:
>> -	if (total_written > 0)
>> -		err = total_written;
>> +	if (total_written > 0) {
>> +		/* Return number of written bytes only if:
>> +		 * 1) SOCK_STREAM socket.
>> +		 * 2) SOCK_SEQPACKET socket when whole buffer is sent.
>> +		 */
>> +		if (sk->sk_type == SOCK_STREAM || total_written == len)
>> +			err = total_written;
>> +	}
>> out:
>> 	release_sock(sk);
>> 	return err;
>> -- 
>> 2.25.1
>>
>