[PATCH net-next 0/3] xsk: support tx napi busy_poll

[menglong8 . dong]

From: Menglong Dong <dongml2@xxxxxxxxxxxxxxx>

For now, we use sk_busy_loop() in __xsk_sendmsg() to send the data in tx
ring. The sk_busy_loop() will poll on the target NAPI. However, for the
nic driver that support the tx napi, such as virtio-net, it can't schedule
the tx NAPI, but only the rx NAPI. If we enable the busy_poll for xsk and
use virtio-net, we can't send data, as the rx NAPI in virtio-net doesn't
handle the packet sending.

Fix this by introduce the sk_tx_busy_loop(), which will poll on the tx
NAPI if available. To get the tx NAPI from the napi_id, we add the
"tx_napi" field to napi_struct, which is ugly :/

Another choice is to call virtnet_xsk_xmit() in virtnet_poll() too. But
this a little contradict the design of tx NAPI.

Menglong Dong (3):
  net: busy-poll: introduce sk_tx_busy_loop()
  virtio_net: initialize napi.tx_napi in virtnet_alloc_queues()
  xsk: replace sk_busy_loop with sk_tx_busy_loop in __xsk_sendmsg()

 drivers/net/virtio_net.c  |  1 +
 include/linux/netdevice.h |  1 +
 include/net/busy_poll.h   | 41 ++++++++++++++++++++++++++++++++++++---
 net/core/dev.c            | 23 +++++-----------------
 net/xdp/xsk.c             |  2 +-
 5 files changed, 46 insertions(+), 22 deletions(-)

-- 
2.54.0