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 <arseny.krasnov@xxxxxxxxxxxxx>
---
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
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