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?
> + 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
