Re: [RFC PATCH v1 08/16] af_vsock: change SEQPACKET receive loop

From: Arseny Krasnov
Date: Wed Jun 30 2021 - 13:48:06 EST



On 30.06.2021 15:12, Stefano Garzarella wrote:
> On Mon, Jun 28, 2021 at 01:03:28PM +0300, Arseny Krasnov wrote:
>> Receive "loop" now really loop: it reads fragments one by
>> one, sleeping if queue is empty.
>>
>> NOTE: 'msg_ready' pointer is not passed to 'seqpacket_dequeue()'
>> here - it change callback interface, so it is moved to next patch.
>>
>> Signed-off-by: Arseny Krasnov <arseny.krasnov@xxxxxxxxxxxxx>
>> ---
>> net/vmw_vsock/af_vsock.c | 31 ++++++++++++++++++++++---------
>> 1 file changed, 22 insertions(+), 9 deletions(-)
> I think you can merge patches 8, 9, and 10 together since we
> are touching the seqpacket_dequeue() behaviour.
>
> Then you can remove in separate patches the unneeded parts (e.g.
> seqpacket_has_data, msg_count, etc.).
>
> Thanks,
> Stefano
Ack
>
>> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>> index 59ce35da2e5b..9552f05119f2 100644
>> --- a/net/vmw_vsock/af_vsock.c
>> +++ b/net/vmw_vsock/af_vsock.c
>> @@ -2003,6 +2003,7 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
>> size_t len, int flags)
>> {
>> const struct vsock_transport *transport;
>> + bool msg_ready;
>> struct vsock_sock *vsk;
>> ssize_t record_len;
>> long timeout;
>> @@ -2013,23 +2014,36 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
>> transport = vsk->transport;
>>
>> timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
>> + msg_ready = false;
>> + record_len = 0;
>>
>> - err = vsock_connectible_wait_data(sk, &wait, timeout, NULL, 0);
>> - if (err <= 0)
>> - goto out;
>> + while (!msg_ready) {
>> + ssize_t fragment_len;
>> + int intr_err;
>>
>> - record_len = transport->seqpacket_dequeue(vsk, msg, flags);
>> + intr_err = vsock_connectible_wait_data(sk, &wait, timeout, NULL, 0);
>> + if (intr_err <= 0) {
>> + err = intr_err;
>> + break;
>> + }
>>
>> - if (record_len < 0) {
>> - err = -ENOMEM;
>> - goto out;
>> + fragment_len = transport->seqpacket_dequeue(vsk, msg, flags);
>> +
>> + if (fragment_len < 0) {
>> + err = -ENOMEM;
>> + break;
>> + }
>> +
>> + record_len += fragment_len;
>> }
>>
>> if (sk->sk_err) {
>> err = -sk->sk_err;
>> } else if (sk->sk_shutdown & RCV_SHUTDOWN) {
>> err = 0;
>> - } else {
>> + }
>> +
>> + if (msg_ready && !err) {
>> /* User sets MSG_TRUNC, so return real length of
>> * packet.
>> */
>> @@ -2045,7 +2059,6 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
>> msg->msg_flags |= MSG_TRUNC;
>> }
>>
>> -out:
>> return err;
>> }
>>
>> --
>> 2.25.1
>>
>