On Fri, Oct 4, 2024 at 3:29 AM Mina Almasry <almasrymina@xxxxxxxxxx> wrote:
>
Hi Mina,
Thanks a lot for the review!
> On Thu, Oct 3, 2024 at 9:07 AM Taehee Yoo <ap420073@xxxxxxxxx> wrote:
> >
> > If driver doesn't support ring parameter or tcp-data-split configuration
> > is not sufficient, the devmem should not be set up.
> > Before setup the devmem, tcp-data-split should be ON and
> > tcp-data-split-thresh value should be 0.
> >
> > Signed-off-by: Taehee Yoo <ap420073@xxxxxxxxx>
> > ---
> >
> > v3:
> > - Patch added.
> >
> > net/core/devmem.c | 18 ++++++++++++++++++
> > 1 file changed, 18 insertions(+)
> >
> > diff --git a/net/core/devmem.c b/net/core/devmem.c
> > index 11b91c12ee11..a9e9b15028e0 100644
> > --- a/net/core/devmem.c
> > +++ b/net/core/devmem.c
> > @@ -8,6 +8,8 @@
> > */
> >
> > #include <linux/dma-buf.h>
> > +#include <linux/ethtool.h>
> > +#include <linux/ethtool_netlink.h>
> > #include <linux/genalloc.h>
> > #include <linux/mm.h>
> > #include <linux/netdevice.h>
> > @@ -131,6 +133,8 @@ int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
> > struct net_devmem_dmabuf_binding *binding,
> > struct netlink_ext_ack *extack)
> > {
> > + struct kernel_ethtool_ringparam kernel_ringparam = {};
> > + struct ethtool_ringparam ringparam = {};
> > struct netdev_rx_queue *rxq;
> > u32 xa_idx;
> > int err;
> > @@ -146,6 +150,20 @@ int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
> > return -EEXIST;
> > }
> >
> > + if (!dev->ethtool_ops->get_ringparam) {
> > + NL_SET_ERR_MSG(extack, "can't get ringparam");
> > + return -EINVAL;
> > + }
> > +
> > + dev->ethtool_ops->get_ringparam(dev, &ringparam,
> > + &kernel_ringparam, extack);
> > + if (kernel_ringparam.tcp_data_split != ETHTOOL_TCP_DATA_SPLIT_ENABLED ||
>
> The way I had set this up is that the driver checks whether header
> split is enabled, and only sets PP_FLAG_ALLOW_UNREADABLE_NETMEM if it
> is. Then core detects that the driver did not allow unreadable netmem
> and it fails that way.
>
> This check is redundant with that. I'm not 100% opposed to redundant
> checks. Maybe they will add some reliability, but also maybe they will
> be confusing to check the same thing essentially in 2 places.
>
> Is the PP_FLAG_ALLOW_UNREADABLE_NETMEM trick not sufficient for you?
Ah okay, I understand.
It looks like it's already validated enough based on
PP_FLAG_ALLOW_UNREADABLE_NETMEM.
I tested how you guided it, and it works as you intended.
It's a duplicated validation indeed, so I will drop this patch in a v4.
Thanks a lot!
Taehee Yoo
>
> > + kernel_ringparam.tcp_data_split_thresh) {
> > + NL_SET_ERR_MSG(extack,
> > + "tcp-header-data-split is disabled or threshold is not zero");
> > + return -EINVAL;
> > + }
> > +
> > #ifdef CONFIG_XDP_SOCKETS
> > if (rxq->pool) {
> > NL_SET_ERR_MSG(extack, "designated queue already in use by AF_XDP");
> > --
> > 2.34.1
> >
>
>
> --
> Thanks,
> Mina
