net: devmem: support TX over NETMEM_TX_NO_DMA devices

When a netkit virtual device leases queues from a physical NIC, devmem
TX bindings created on the netkit device must still result in the dmabuf
being mapped for dma by the physical device. This patch accomplishes
this by teaching the bind handler to search for the underlying
DMA-capable device by looking it up via leased rx queues. The function
netdev_find_netmem_tx_dev(), used for finding the underlying DMA-capable
device, can be extended to support other non-netkit NETMEM_TX_NO_DMA
devices in the future if needed.

Additionally, this patch extends validate_xmit_unreadable_skb() to
support the netkit case, where the skb is validated twice: once on the
netkit guest device and again on the physical NIC after BPF redirect or
ip forwarding.

Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
Link: https://patch.msgid.link/20260514-tcp-dm-netkit-v5-3-408c59b91e66@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions