Re: [dpdk-dev] [PATCH v3] net/virtio: fix wrong variable assignment in helper macro

["Xia, Chenbo" <chenbo.xia@intel.com>]

> -----Original Message-----
> From: Vipul Ashri <vipul.ashri@oracle.com>
> Sent: Thursday, August 13, 2020 3:29 PM
> To: dev@dpdk.org
> Cc: Xia, Chenbo <chenbo.xia@intel.com>; vipul.ashri@oracle.com;
> edwin.leung@oracle.com; stable@dpdk.org
> Subject: [PATCH v3] net/virtio: fix wrong variable assignment in helper
> macro
> 
> Inside Macro ASSIGN_UNLESS_EQUAL(var, val), assignment to var is always
> failing as assignment done using var_ having local scope only.
> This leads to TX packets not going out and found broken due to cleanup
> malfunctioning. This patch fixes the wrong variable assignment.
> 
> Fixes: 57f90f894588 ("net/virtio: reuse packed ring functions")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Vipul Ashri <vipul.ashri@oracle.com>
> ---
>  drivers/net/virtio/virtqueue.h | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtqueue.h
> b/drivers/net/virtio/virtqueue.h
> index 105a9c00c..20c95471e 100644
> --- a/drivers/net/virtio/virtqueue.h
> +++ b/drivers/net/virtio/virtqueue.h
> @@ -607,10 +607,8 @@ virtqueue_notify(struct virtqueue *vq)
> 
>  /* avoid write operation when necessary, to lessen cache issues */
>  #define ASSIGN_UNLESS_EQUAL(var, val) do {	\
> -	typeof(var) var_ = (var);		\
> -	typeof(val) val_ = (val);		\
> -	if ((var_) != (val_))			\
> -		(var_) = (val_);		\
> +	if ((var) != (val))			\
> +		(var) = (val);			\
>  } while (0)
> 
>  #define virtqueue_clear_net_hdr(hdr) do {		\
> --
> 2.28.0.windows.1

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>