Re: [Qemu-devel] [PATCH] net: cadence_gem: clear RX control descriptor

[Jason Wang <jasowang@redhat.com>]

On 2019/6/15 下午1:17, Ramon Fried wrote:
> The RX ring descriptors control field is used for setting
> SOF and EOF (start of frame and end of frame).
> The SOF and EOF weren't cleared from the previous descriptors,
> causing inconsistencies in ring buffer.
> Fix that by clearing the control field of every descriptors we're
> processing.
>
> Signed-off-by: Ramon Fried <rfried.dev@gmail.com>
> ---
>   hw/net/cadence_gem.c | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
> index ecee22525c..d83a82bdb0 100644
> --- a/hw/net/cadence_gem.c
> +++ b/hw/net/cadence_gem.c
> @@ -406,6 +406,11 @@ static inline void rx_desc_set_sof(uint32_t *desc)
>       desc[1] |= DESC_1_RX_SOF;
>   }
>   
> +static inline void rx_desc_clear(uint32_t *desc)


Nit: is this better to name this as "rx_desc_clear_control()" ?

Thanks


> +{
> +    desc[1]  = 0;
> +}
> +
>   static inline void rx_desc_set_eof(uint32_t *desc)
>   {
>       desc[1] |= DESC_1_RX_EOF;
> @@ -994,6 +999,8 @@ static ssize_t gem_receive(NetClientState *nc, const uint8_t *buf, size_t size)
>           bytes_to_copy -= MIN(bytes_to_copy, rxbufsize);
>   
>           /* Update the descriptor.  */
> +        rx_desc_clear(s->rx_desc[q]);
> +
>           if (first_desc) {
>               rx_desc_set_sof(s->rx_desc[q]);
>               first_desc = false;