On 30.07.2024 01:51, Amery Hung wrote:
> On Mon, Jul 29, 2024 at 1:12 PM Arseniy Krasnov
> <avkrasnov@xxxxxxxxxxxxxxxxx> wrote:
>>
>> Hi,
>>
>>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>>> index a1c76836d798..46cd1807f8e3 100644
>>> --- a/net/vmw_vsock/virtio_transport_common.c
>>> +++ b/net/vmw_vsock/virtio_transport_common.c
>>> @@ -1040,13 +1040,98 @@ int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
>>> }
>>> EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
>>>
>>> +static int virtio_transport_dgram_send_pkt_info(struct vsock_sock *vsk,
>>> + struct virtio_vsock_pkt_info *info)
>>> +{
>>> + u32 src_cid, src_port, dst_cid, dst_port;
>>> + const struct vsock_transport *transport;
>>> + const struct virtio_transport *t_ops;
>>> + struct sock *sk = sk_vsock(vsk);
>>> + struct virtio_vsock_hdr *hdr;
>>> + struct sk_buff *skb;
>>> + void *payload;
>>> + int noblock = 0;
>>> + int err;
>>> +
>>> + info->type = virtio_transport_get_type(sk_vsock(vsk));
>>> +
>>> + if (info->pkt_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
>>> + return -EMSGSIZE;
>>
>> Small suggestion, i think we can check for packet length earlier ? Before
>> info->type = ...
>
> Certainly.
>
>>
>>> +
>>> + transport = vsock_dgram_lookup_transport(info->remote_cid, info->remote_flags);
>>> + t_ops = container_of(transport, struct virtio_transport, transport);
>>> + if (unlikely(!t_ops))
>>> + return -EFAULT;
>>> +
>>> + if (info->msg)
>>> + noblock = info->msg->msg_flags & MSG_DONTWAIT;
>>> +
>>> + /* Use sock_alloc_send_skb to throttle by sk_sndbuf. This helps avoid
>>> + * triggering the OOM.
>>> + */
>>> + skb = sock_alloc_send_skb(sk, info->pkt_len + VIRTIO_VSOCK_SKB_HEADROOM,
>>> + noblock, &err);
>>> + if (!skb)
>>> + return err;
>>> +
>>> + skb_reserve(skb, VIRTIO_VSOCK_SKB_HEADROOM);
>>> +
>>> + src_cid = t_ops->transport.get_local_cid();
>>> + src_port = vsk->local_addr.svm_port;
>>> + dst_cid = info->remote_cid;
>>> + dst_port = info->remote_port;
>>> +
>>> + hdr = virtio_vsock_hdr(skb);
>>> + hdr->type = cpu_to_le16(info->type);
>>> + hdr->op = cpu_to_le16(info->op);
>>> + hdr->src_cid = cpu_to_le64(src_cid);
>>> + hdr->dst_cid = cpu_to_le64(dst_cid);
>>> + hdr->src_port = cpu_to_le32(src_port);
>>> + hdr->dst_port = cpu_to_le32(dst_port);
>>> + hdr->flags = cpu_to_le32(info->flags);
>>> + hdr->len = cpu_to_le32(info->pkt_len);
>>
>> There is function 'virtio_transport_init_hdr()' in this file, may be reuse it ?
>
> Will do.
>
>>
>>> +
>>> + if (info->msg && info->pkt_len > 0) {
>>
>> If pkt_len is 0, do we really need to send such packets ? Because for connectible
>> sockets, we ignore empty OP_RW packets.
>
> Thanks for pointing this out. I think virtio dgram should also follow that.
>
>>
>>> + payload = skb_put(skb, info->pkt_len);
>>> + err = memcpy_from_msg(payload, info->msg, info->pkt_len);
>>> + if (err)
>>> + goto out;
>>> + }
>>> +
>>> + trace_virtio_transport_alloc_pkt(src_cid, src_port,
>>> + dst_cid, dst_port,
>>> + info->pkt_len,
>>> + info->type,
>>> + info->op,
>>> + info->flags,
>>> + false);
>>
>> ^^^ For SOCK_DGRAM, include/trace/events/vsock_virtio_transport_common.h also should
>> be updated?
>
> Can you elaborate what needs to be changed?
Sure, there are:
TRACE_DEFINE_ENUM(VIRTIO_VSOCK_TYPE_STREAM);
TRACE_DEFINE_ENUM(VIRTIO_VSOCK_TYPE_SEQPACKET);
#define show_type(val) \
__print_symbolic(val, \
{ VIRTIO_VSOCK_TYPE_STREAM, "STREAM" }, \
{ VIRTIO_VSOCK_TYPE_SEQPACKET, "SEQPACKET" })
I guess SOCK_DGRAM handling should be added to print type of socket.
Thanks, Arseniy
>
> Thank you,
> Amery
>
>>
>>> +
>>> + return t_ops->send_pkt(skb);
>>> +out:
>>> + kfree_skb(skb);
>>> + return err;
>>> +}
>>> +
>>> int
>>> virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
>>> struct sockaddr_vm *remote_addr,
>>> struct msghdr *msg,
>>> size_t dgram_len)
>>> {
>>> - return -EOPNOTSUPP;
>>> + /* Here we are only using the info struct to retain style uniformity
>>> + * and to ease future refactoring and merging.
>>> + */
>>> + struct virtio_vsock_pkt_info info = {
>>> + .op = VIRTIO_VSOCK_OP_RW,
>>> + .remote_cid = remote_addr->svm_cid,
>>> + .remote_port = remote_addr->svm_port,
>>> + .remote_flags = remote_addr->svm_flags,
>>> + .msg = msg,
>>> + .vsk = vsk,
>>> + .pkt_len = dgram_len,
>>> + };
>>> +
>>> + return virtio_transport_dgram_send_pkt_info(vsk, &info);
>>> }
>>> EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
>>>
>>> --
>>> 2.20.1
>>
>> Thanks, Arseniy
