Re: [Qemu-devel] [PATCH arm-devs v1 04/13] net/cadence_gem: simplify rx buf descriptor walking

[Peter Maydell]

On 2 December 2013 07:11, Peter Crosthwaite
<address@hidden> wrote:
> There was a replication of the rx descriptor address walking logic.
> Reorder the flow control to remove. This refactoring also obsoletes
> the local variables packet_desc_addr and last_desc_addr.
>
> Signed-off-by: Peter Crosthwaite <address@hidden>
> ---
>
>  hw/net/cadence_gem.c | 39 ++++++++++-----------------------------
>  1 file changed, 10 insertions(+), 29 deletions(-)
>
> diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
> index 3f30caf..73ac0d8 100644
> --- a/hw/net/cadence_gem.c
> +++ b/hw/net/cadence_gem.c
> @@ -586,7 +586,6 @@ static int gem_mac_address_filter(GemState *s, const 
> uint8_t *packet)
>  static ssize_t gem_receive(NetClientState *nc, const uint8_t *buf, size_t 
> size)
>  {
>      unsigned    desc[2];
> -    hwaddr packet_desc_addr, last_desc_addr;
>      GemState *s;
>      unsigned   rxbufsize, bytes_to_copy;
>      unsigned   rxbuf_offset;
> @@ -667,17 +666,16 @@ static ssize_t gem_receive(NetClientState *nc, const 
> uint8_t *buf, size_t size)
>
>      DB_PRINT("config bufsize: %d packet size: %ld\n", rxbufsize, size);
>
> -    packet_desc_addr = s->rx_desc_addr;
> -    while (1) {
> -        DB_PRINT("read descriptor 0x%x\n", (unsigned)packet_desc_addr);
> +    while (bytes_to_copy) {
> +        DB_PRINT("read descriptor 0x%x\n", (unsigned)s->rx_desc_addr);

Can we get here with bytes_to_copy == 0 ?  The logic sets size to a minimum
of 64 bytes but we've already set up bytes_to_copy before that.

-- PMM