On Fri, Dec 14, 2018 at 02:30:35PM +0100, Marek Vasut wrote:
> On 12/14/2018 10:05 AM, Andrew Lunn wrote:
> >> +static struct sk_buff *ksz_common_xmit(struct sk_buff *skb,
> >> + struct net_device *dev, int len)
> >> {
> >> - struct dsa_port *dp = dsa_slave_to_port(dev);
> >> struct sk_buff *nskb;
> >> int padlen;
> >> - u8 *tag;
> >>
> >> padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len;
> >>
> >> - if (skb_tailroom(skb) >= padlen + KSZ_INGRESS_TAG_LEN) {
> >> + if (skb_tailroom(skb) >= padlen + len) {
> >> /* Let dsa_slave_xmit() free skb */
> >> if (__skb_put_padto(skb, skb->len + padlen, false))
> >> return NULL;
> >
> > Hi Marek
>
> Hi,
>
> > This can return NULL.
> >
> >> +static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
> >> + struct net_device *dev)
> >> +{
> >> + struct dsa_port *dp = dsa_slave_to_port(dev);
> >> + struct sk_buff *nskb;
> >> + u16 *tag;
> >> + u8 *addr;
> >> +
> >> + nskb = ksz_common_xmit(skb, dev, KSZ9477_INGRESS_TAG_LEN);
> >
> > So here you need to check for NULL
>
> What do we do if the xmit returns NULL ?
Return NULL to the caller. There are comments which explain this:
static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
{
[snip]
/* Transmit function may have to reallocate the original SKB,
* in which case it must have freed it. Only free it here on error.
*/
nskb = p->xmit(skb, dev);
if (!nskb) {
kfree_skb(skb);
return NETDEV_TX_OK;
}
Andrew
