[PATCH net-next v5 3/5] vsock/virtio: fix locking in virtio_transport_inc_tx_pkt()

[Stefano Garzarella]

fwd_cnt and last_fwd_cnt are protected by rx_lock, so we should use
the same spinlock also if we are in the TX path.

Move also buf_alloc under the same lock.

Signed-off-by: Stefano Garzarella <sgarz...@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
Acked-by: Michael S. Tsirkin <m...@redhat.com>
---
 include/linux/virtio_vsock.h            | 2 +-
 net/vmw_vsock/virtio_transport_common.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 49fc9d20bc43..4c7781f4b29b 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -35,7 +35,6 @@ struct virtio_vsock_sock {
 
        /* Protected by tx_lock */
        u32 tx_cnt;
-       u32 buf_alloc;
        u32 peer_fwd_cnt;
        u32 peer_buf_alloc;
 
@@ -43,6 +42,7 @@ struct virtio_vsock_sock {
        u32 fwd_cnt;
        u32 last_fwd_cnt;
        u32 rx_bytes;
+       u32 buf_alloc;
        struct list_head rx_queue;
 };
 
diff --git a/net/vmw_vsock/virtio_transport_common.c 
b/net/vmw_vsock/virtio_transport_common.c
index a85559d4d974..34a2b42313b7 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -210,11 +210,11 @@ static void virtio_transport_dec_rx_pkt(struct 
virtio_vsock_sock *vvs,
 
 void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct 
virtio_vsock_pkt *pkt)
 {
-       spin_lock_bh(&vvs->tx_lock);
+       spin_lock_bh(&vvs->rx_lock);
        vvs->last_fwd_cnt = vvs->fwd_cnt;
        pkt->hdr.fwd_cnt = cpu_to_le32(vvs->fwd_cnt);
        pkt->hdr.buf_alloc = cpu_to_le32(vvs->buf_alloc);
-       spin_unlock_bh(&vvs->tx_lock);
+       spin_unlock_bh(&vvs->rx_lock);
 }
 EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
 
-- 
2.20.1