Re: [PATCH] cleanup large frame handling for natsemi.c

[Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>]

Jeff Garzik wrote:

> On Sun, Jun 20, 2004 at 06:43:07PM +0200, Manfred Spraul wrote:
>  
>
> > @@ -1909,9 +1916,13 @@
> >         np->dirty_rx = 0;
> >         np->cur_rx = RX_RING_SIZE;
> >         np->oom = 0;
> > -       np->rx_buf_sz = PKT_BUF_SZ;
> > -       if (dev->mtu > ETH_DATA_LEN)
> > -               np->rx_buf_sz += dev->mtu - ETH_DATA_LEN;
> > +       if (dev->mtu <= ETH_DATA_LEN)
> > +               np->rx_buf_sz = ETH_DATA_LEN + NATSEMI_HEADERS;
> > +       else
> > +               np->rx_buf_sz = dev->mtu + NATSEMI_HEADERS;
> > +       if (np->rx_buf_sz > NATSEMI_RX_LIMIT)
> > +               np->rx_buf_sz = NATSEMI_RX_LIMIT;
> > +
> >    
> Double NAK:
>
> 1) Use PKT_BUF_SZ, don't alloc smaller than that.
>
>  
The alloc size is never smaller than PKT_BUF_SZ: 
ETH_DATA_LEN+NATSEMI_HEADERS+NATSEMI_PADDING is 1586 bytes [still 
smaller than the 1620 byte skb kmalloc cache]
> 2) The final check should not be needed.  The code should guarantee that
> np->rx_buf_sz never exceeds NATSEMI_RX_LIMIT.
>
>  
You mean: implement a change_mtu callback and reject mtu values above 
2020 byte?
--
   Manfred

>         Jeff
>
>
>