Stefano Garzarella
2021-Mar-12 15:20 UTC
[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 <arseny.krasnov at kaspersky.com> >--- > 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 >