Re: [Qemu-devel] [Qemu-trivial] [PATCH 1/1] virtio: pass argument by value for virtqueue_map_iovec()

[Laurent Vivier]

CC: Paolo as the use of modified num_sg has been removed by his patch:

  3b3b062821 virtio: slim down allocation of VirtQueueElements

On 02/11/2018 07:16, Dongli Zhang wrote:
> Pass num_sg by value instead of by pointer, as num_sg is never modified in
> virtqueue_map_iovec().
> 
> Signed-off-by: Dongli Zhang <address@hidden>
> ---
>  hw/virtio/virtio.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 4136d23..a5cb4e6 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -796,13 +796,13 @@ static void virtqueue_undo_map_desc(unsigned int 
> out_num, unsigned int in_num,
>  }
>  
>  static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg,
> -                                hwaddr *addr, unsigned int *num_sg,
> +                                hwaddr *addr, unsigned int num_sg,
>                                  int is_write)
>  {
>      unsigned int i;
>      hwaddr len;
>  
> -    for (i = 0; i < *num_sg; i++) {
> +    for (i = 0; i < num_sg; i++) {
>          len = sg[i].iov_len;
>          sg[i].iov_base = dma_memory_map(vdev->dma_as,
>                                          addr[i], &len, is_write ?
> @@ -821,8 +821,8 @@ static void virtqueue_map_iovec(VirtIODevice *vdev, 
> struct iovec *sg,
>  
>  void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem)
>  {
> -    virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, &elem->in_num, 1);
> -    virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, &elem->out_num, 
> 0);
> +    virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, elem->in_num, 1);
> +    virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, elem->out_num, 
> 0);
>  }
>  
>  static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned 
> in_num)
>