Re: [RFC PATCH v1 3/7] vhost/vsock: support MSG_EOR bit processing

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>,
	Norbert Slusarek <nslusarek@gmx.net>,
	Andra Paraschiv <andraprs@amazon.com>,
	Colin Ian King <colin.king@canonical.com>,
	"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>,
	"oxffffaa@gmail.com" <oxffffaa@gmail.com>
Subject: Re: [RFC PATCH v1 3/7] vhost/vsock: support MSG_EOR bit processing
Date: Fri, 6 Aug 2021 11:40:38 +0300	[thread overview]
Message-ID: <40a1d508-c841-23b7-58d5-f539b2d98ae1@kaspersky.com> (raw)
In-Reply-To: <20210806072849.4by3wbdkg2bsierm@steredhat>

On 06.08.2021 10:28, Stefano Garzarella wrote:
> Caution: This is an external email. Be cautious while opening links or attachments.
>
>
>
> On Mon, Jul 26, 2021 at 07:33:38PM +0300, Arseny Krasnov wrote:
>> It works in the same way as 'end-of-message' bit: if packet has
>> 'EOM' bit, also check for 'EOR' bit.
>>
>> Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>> ---
>> drivers/vhost/vsock.c | 12 +++++++++++-
>> 1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
>> index 3b55de70ac77..3e2b150f9c6f 100644
>> --- a/drivers/vhost/vsock.c
>> +++ b/drivers/vhost/vsock.c
>> @@ -115,6 +115,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
>>               size_t iov_len, payload_len;
>>               int head;
>>               bool restore_msg_eom_flag = false;
>> +              bool restore_msg_eor_flag = false;
> Since we now have 2 flags to potentially restore, we could use a single
> variable (e.g. uint32_t flags_to_restore), initialized to 0.
>
> We can set all the flags we need to restore and then simply put it
> in or with the `pkt->hdr.flags` field.
>
>>               spin_lock_bh(&vsock->send_pkt_list_lock);
>>               if (list_empty(&vsock->send_pkt_list)) {
>> @@ -188,6 +189,11 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
>>                       if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM) {
>>                               pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
>>                               restore_msg_eom_flag = true;
>> +
>> +                              if (le32_to_cpu(pkt->hdr.flags & VIRTIO_VSOCK_SEQ_EOR)) {
>                                                                 ^
> Here it should be `le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR`
>
>> +                                      pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
>> +                                      restore_msg_eor_flag = true;
>> +                              }
>>                       }
>>               }
>>
>> @@ -224,9 +230,13 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
>>                * to send it with the next available buffer.
>>                */
>>               if (pkt->off < pkt->len) {
>> -                      if (restore_msg_eom_flag)
>> +                      if (restore_msg_eom_flag) {
>>                               pkt->hdr.flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
>>
>> +                              if (restore_msg_eor_flag)
>> +                                      pkt->hdr.flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
>> +                      }
>> +
> If we use a single variable, here we can simply do:
>
>                         pkt->hdr.flags |= cpu_to_le32(flags_to_restore);
>
> Stefano

Thanks, i'll prepare v2 both with spec patch. About spec: i've already sent

patch for SEQPACKET, can i prepare spec patch updating current reviewed

SEQPACKET? E.g. i'll include both EOM and EOR in one patch.

Thank You

>