On Mon, Aug 08, 2016 at 08:23:55PM -0700, Benjamin Poirier wrote:
> On 2016/08/08 09:26, Andreas Werner wrote:
> [...]
> > > > +
> > > > + if (cf->can_dlc > 0)
> > > > + data[0] = be32_to_cpup((__be32 *)(cf->data));
> > > > + if (cf->can_dlc > 3)
> > > > + data[1] = be32_to_cpup((__be32 *)(cf->data + 4));
> > > > +
> > > > + writel(id, &cf_buf->can_id);
> > > > + writel(cf->can_dlc, &cf_buf->length);
> > > > +
> > > > + if (!(cf->can_id & CAN_RTR_FLAG)) {
> > > > + writel(data[0], &cf_buf->data[0]);
> > > > + writel(data[1], &cf_buf->data[1]);
> > > > +
> > > > + stats->tx_bytes += cf->can_dlc;
> > > > + }
> > > > +
> > > > + /* be sure everything is written to the
> > > > + * device before acknowledge the data.
> > > > + */
> > > > + mmiowb();
> > > > +
> > > > + /* trigger the transmission */
> > > > + men_z192_ack_tx_pkg(priv, 1);
> > > > +
> > > > + stats->tx_packets++;
> > > > +
> > > > + kfree_skb(skb);
> > >
> > > What prevents the skb data to be freed/reused before the device has
> > > accessed it?
>
> I'm sorry, I hadn't realized that all of the data (all 8 bytes of it!)
> is written directly to the device. I was thinking about ethernet devices
> that dma packet data.
Ah ok :-)
I thought you just want me to free the skb earlier.
Regards
Andy
