2021-03-08 07:38:18

by Arseny Krasnov

Subject: [RFC PATCH v6 12/22] virtio/vsock: fetch length for SEQPACKET record

This adds transport callback which tries to fetch record begin marker
from socket's rx queue. It is called from af_vsock.c before reading data
packets of record.

Signed-off-by: Arseny Krasnov <[email protected]>
---
include/linux/virtio_vsock.h | 1 +
net/vmw_vsock/virtio_transport_common.c | 53 +++++++++++++++++++++++++
2 files changed, 54 insertions(+)

diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 466a5832d2f5..d7edcfeb4cd2 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -88,6 +88,7 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
size_t len, int flags);

+size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk);
int
virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 5f1e283e43f3..6fc78fec41c0 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -399,6 +399,59 @@ static inline void virtio_transport_remove_pkt(struct virtio_vsock_pkt *pkt)
virtio_transport_free_pkt(pkt);
}

+static size_t virtio_transport_drop_until_seq_begin(struct virtio_vsock_sock *vvs)
+{
+ struct virtio_vsock_pkt *pkt, *n;
+ size_t bytes_dropped = 0;
+
+ list_for_each_entry_safe(pkt, n, &vvs->rx_queue, list) {
+ if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_SEQ_BEGIN)
+ break;
+
+ bytes_dropped += le32_to_cpu(pkt->hdr.len);
+ virtio_transport_dec_rx_pkt(vvs, pkt);
+ virtio_transport_remove_pkt(pkt);
+ }
+
+ return bytes_dropped;
+}
+
+size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk)
+{
+ struct virtio_vsock_seq_hdr *seq_hdr;
+ struct virtio_vsock_sock *vvs;
+ struct virtio_vsock_pkt *pkt;
+ size_t bytes_dropped;
+
+ vvs = vsk->trans;
+
+ spin_lock_bh(&vvs->rx_lock);
+
+ /* Fetch all orphaned 'RW' packets and send credit update. */
+ bytes_dropped = virtio_transport_drop_until_seq_begin(vvs);
+
+ if (list_empty(&vvs->rx_queue))
+ goto out;
+
+ pkt = list_first_entry(&vvs->rx_queue, struct virtio_vsock_pkt, list);
+
+ vvs->seqpacket_state.user_read_copied = 0;
+
+ seq_hdr = (struct virtio_vsock_seq_hdr *)pkt->buf;
+ vvs->seqpacket_state.user_read_seq_len = le32_to_cpu(seq_hdr->msg_len);
+ vvs->seqpacket_state.curr_rx_msg_id = le32_to_cpu(seq_hdr->msg_id);
+ virtio_transport_dec_rx_pkt(vvs, pkt);
+ virtio_transport_remove_pkt(pkt);
+out:
+ spin_unlock_bh(&vvs->rx_lock);
+
+ if (bytes_dropped)
+ virtio_transport_send_credit_update(vsk);
+
+ return vvs->seqpacket_state.user_read_seq_len;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_seq_get_len);
+
static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
bool *msg_ready)
--
2.25.1

2021-03-12 15:23:16

by Stefano Garzarella

Subject: Re: [RFC PATCH v6 12/22] virtio/vsock: fetch length for SEQPACKET record

On Sun, Mar 07, 2021 at 09:02:31PM +0300, Arseny Krasnov wrote:
>This adds transport callback which tries to fetch record begin marker
>from socket's rx queue. It is called from af_vsock.c before reading data
>packets of record.
>
>Signed-off-by: Arseny Krasnov <[email protected]>
>---
> include/linux/virtio_vsock.h | 1 +
> net/vmw_vsock/virtio_transport_common.c | 53 +++++++++++++++++++++++++
> 2 files changed, 54 insertions(+)
>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index 466a5832d2f5..d7edcfeb4cd2 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -88,6 +88,7 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> struct msghdr *msg,
> size_t len, int flags);
>
>+size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk);
> int
> virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
> struct msghdr *msg,
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index 5f1e283e43f3..6fc78fec41c0 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -399,6 +399,59 @@ static inline void virtio_transport_remove_pkt(struct virtio_vsock_pkt *pkt)
> virtio_transport_free_pkt(pkt);
> }
>
>+static size_t virtio_transport_drop_until_seq_begin(struct virtio_vsock_sock *vvs)
>+{
>+ struct virtio_vsock_pkt *pkt, *n;
>+ size_t bytes_dropped = 0;
>+
>+ list_for_each_entry_safe(pkt, n, &vvs->rx_queue, list) {
>+ if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_SEQ_BEGIN)
>+ break;
>+
>+ bytes_dropped += le32_to_cpu(pkt->hdr.len);
>+ virtio_transport_dec_rx_pkt(vvs, pkt);
>+ virtio_transport_remove_pkt(pkt);
>+ }
>+
>+ return bytes_dropped;
>+}
>+
>+size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk)
>+{
>+ struct virtio_vsock_seq_hdr *seq_hdr;
>+ struct virtio_vsock_sock *vvs;
>+ struct virtio_vsock_pkt *pkt;
>+ size_t bytes_dropped;
>+
>+ vvs = vsk->trans;
>+
>+ spin_lock_bh(&vvs->rx_lock);
>+
>+ /* Fetch all orphaned 'RW' packets and send credit update. */
>+ bytes_dropped = virtio_transport_drop_until_seq_begin(vvs);
>+
>+ if (list_empty(&vvs->rx_queue))
>+ goto out;

What do we return to in this case?

IIUC we return the len of the previous packet, should we set
vvs->seqpacket_state.user_read_seq_len to 0?

>+
>+ pkt = list_first_entry(&vvs->rx_queue, struct virtio_vsock_pkt, list);
>+
>+ vvs->seqpacket_state.user_read_copied = 0;
>+
>+ seq_hdr = (struct virtio_vsock_seq_hdr *)pkt->buf;
>+ vvs->seqpacket_state.user_read_seq_len =
>le32_to_cpu(seq_hdr->msg_len);
>+ vvs->seqpacket_state.curr_rx_msg_id = le32_to_cpu(seq_hdr->msg_id);
>+ virtio_transport_dec_rx_pkt(vvs, pkt);
>+ virtio_transport_remove_pkt(pkt);
>+out:
>+ spin_unlock_bh(&vvs->rx_lock);
>+
>+ if (bytes_dropped)
>+ virtio_transport_send_credit_update(vsk);
>+
>+ return vvs->seqpacket_state.user_read_seq_len;
>+}
>+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_seq_get_len);
>+
> static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
> struct msghdr *msg,
> bool *msg_ready)
>--
>2.25.1
>

2021-03-15 07:50:54

by Arseny Krasnov

Subject: Re: [RFC PATCH v6 12/22] virtio/vsock: fetch length for SEQPACKET record

On 12.03.2021 18:20, Stefano Garzarella wrote:
> On Sun, Mar 07, 2021 at 09:02:31PM +0300, Arseny Krasnov wrote:
>> This adds transport callback which tries to fetch record begin marker
> >from socket's rx queue. It is called from af_vsock.c before reading data
>> packets of record.
>>
>> Signed-off-by: Arseny Krasnov <[email protected]>
>> ---
>> include/linux/virtio_vsock.h | 1 +
>> net/vmw_vsock/virtio_transport_common.c | 53 +++++++++++++++++++++++++
>> 2 files changed, 54 insertions(+)
>>
>> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>> index 466a5832d2f5..d7edcfeb4cd2 100644
>> --- a/include/linux/virtio_vsock.h
>> +++ b/include/linux/virtio_vsock.h
>> @@ -88,6 +88,7 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
>> struct msghdr *msg,
>> size_t len, int flags);
>>
>> +size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk);
>> int
>> virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
>> struct msghdr *msg,
>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>> index 5f1e283e43f3..6fc78fec41c0 100644
>> --- a/net/vmw_vsock/virtio_transport_common.c
>> +++ b/net/vmw_vsock/virtio_transport_common.c
>> @@ -399,6 +399,59 @@ static inline void virtio_transport_remove_pkt(struct virtio_vsock_pkt *pkt)
>> virtio_transport_free_pkt(pkt);
>> }
>>
>> +static size_t virtio_transport_drop_until_seq_begin(struct virtio_vsock_sock *vvs)
>> +{
>> + struct virtio_vsock_pkt *pkt, *n;
>> + size_t bytes_dropped = 0;
>> +
>> + list_for_each_entry_safe(pkt, n, &vvs->rx_queue, list) {
>> + if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_SEQ_BEGIN)
>> + break;
>> +
>> + bytes_dropped += le32_to_cpu(pkt->hdr.len);
>> + virtio_transport_dec_rx_pkt(vvs, pkt);
>> + virtio_transport_remove_pkt(pkt);
>> + }
>> +
>> + return bytes_dropped;
>> +}
>> +
>> +size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk)
>> +{
>> + struct virtio_vsock_seq_hdr *seq_hdr;
>> + struct virtio_vsock_sock *vvs;
>> + struct virtio_vsock_pkt *pkt;
>> + size_t bytes_dropped;
>> +
>> + vvs = vsk->trans;
>> +
>> + spin_lock_bh(&vvs->rx_lock);
>> +
>> + /* Fetch all orphaned 'RW' packets and send credit update. */
>> + bytes_dropped = virtio_transport_drop_until_seq_begin(vvs);
>> +
>> + if (list_empty(&vvs->rx_queue))
>> + goto out;
> What do we return to in this case?
>
> IIUC we return the len of the previous packet, should we set
> vvs->seqpacket_state.user_read_seq_len to 0?
Yes, i think that's true
>
>> +
>> + pkt = list_first_entry(&vvs->rx_queue, struct virtio_vsock_pkt, list);
>> +
>> + vvs->seqpacket_state.user_read_copied = 0;
>> +
>> + seq_hdr = (struct virtio_vsock_seq_hdr *)pkt->buf;
>> + vvs->seqpacket_state.user_read_seq_len =
>> le32_to_cpu(seq_hdr->msg_len);
>> + vvs->seqpacket_state.curr_rx_msg_id = le32_to_cpu(seq_hdr->msg_id);
>> + virtio_transport_dec_rx_pkt(vvs, pkt);
>> + virtio_transport_remove_pkt(pkt);
>> +out:
>> + spin_unlock_bh(&vvs->rx_lock);
>> +
>> + if (bytes_dropped)
>> + virtio_transport_send_credit_update(vsk);
>> +
>> + return vvs->seqpacket_state.user_read_seq_len;
>> +}
>> +EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_seq_get_len);
>> +
>> static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
>> struct msghdr *msg,
>> bool *msg_ready)
>> --
>> 2.25.1
>>
>