virtio_vsock_skb_rx_put() only calls skb_put() if the length in the packet header is not zero even though skb_put() handles this case gracefully.
Remove the functionally redundant check from virtio_vsock_skb_rx_put() and, on the assumption that this is a worthwhile optimisation for handling credit messages, augment the existing length checks in virtio_transport_rx_work() to elide the call for zero-length payloads. Since the callers all have the length, extend virtio_vsock_skb_rx_put() to take it as an additional parameter rather than fish it back out of the packet header. Note that the vhost code already has similar logic in vhost_vsock_alloc_skb(). Reviewed-by: Stefano Garzarella <sgarz...@redhat.com> Signed-off-by: Will Deacon <w...@kernel.org> --- drivers/vhost/vsock.c | 2 +- include/linux/virtio_vsock.h | 9 ++------- net/vmw_vsock/virtio_transport.c | 4 +++- 3 files changed, 6 insertions(+), 9 deletions(-) diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 66a0f060770e..4c4a642945eb 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -375,7 +375,7 @@ vhost_vsock_alloc_skb(struct vhost_virtqueue *vq, return NULL; } - virtio_vsock_skb_rx_put(skb); + virtio_vsock_skb_rx_put(skb, payload_len); nbytes = copy_from_iter(skb->data, payload_len, &iov_iter); if (nbytes != payload_len) { diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h index 36fb3edfa403..97465f378ade 100644 --- a/include/linux/virtio_vsock.h +++ b/include/linux/virtio_vsock.h @@ -47,14 +47,9 @@ static inline void virtio_vsock_skb_clear_tap_delivered(struct sk_buff *skb) VIRTIO_VSOCK_SKB_CB(skb)->tap_delivered = false; } -static inline void virtio_vsock_skb_rx_put(struct sk_buff *skb) +static inline void virtio_vsock_skb_rx_put(struct sk_buff *skb, u32 len) { - u32 len; - - len = le32_to_cpu(virtio_vsock_hdr(skb)->len); - - if (len > 0) - skb_put(skb, len); + skb_put(skb, len); } static inline struct sk_buff *virtio_vsock_alloc_skb(unsigned int size, gfp_t mask) diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index eb08a393413d..0166919f8705 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -656,7 +656,9 @@ static void virtio_transport_rx_work(struct work_struct *work) continue; } - virtio_vsock_skb_rx_put(skb); + if (payload_len) + virtio_vsock_skb_rx_put(skb, payload_len); + virtio_transport_deliver_tap_pkt(skb); virtio_transport_recv_pkt(&virtio_transport, skb); } -- 2.50.0.727.gbf7dc18ff4-goog