virtio/vsock: check argument to avoid no effect call

Both of these functions have no effect when input argument is 0, so to
avoid useless spinlock access, check argument before it.

Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 8c60fc7f94a58d068f31249a5bc889dea963cdf4..7fc178c3ee07bf1a8340ed6c5079d038288aa338 100644 (file)
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -302,6 +302,9 @@ u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 credit)
 {
        u32 ret;
 
+       if (!credit)
+               return 0;
+
        spin_lock_bh(&vvs->tx_lock);
        ret = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
        if (ret > credit)
@@ -315,6 +318,9 @@ EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
 
 void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit)
 {
+       if (!credit)
+               return;
+
        spin_lock_bh(&vvs->tx_lock);
        vvs->tx_cnt -= credit;
        spin_unlock_bh(&vvs->tx_lock);