virtio-net: don't schedule delayed refill worker

virtio-net: don't schedule delayed refill worker

When we fail to refill the receive buffers, we schedule a delayed worker
to retry later. However, this worker creates some concurrency issues.
For example, when the worker runs concurrently with virtnet_xdp_set,
both need to temporarily disable queue's NAPI before enabling again.
Without proper synchronization, a deadlock can happen when
napi_disable() is called on an already disabled NAPI. That
napi_disable() call will be stuck and so will the subsequent
napi_enable() call.

To simplify the logic and avoid further problems, we will instead retry
refilling in the next NAPI poll.

Fixes: 4bc12818b363 ("virtio-net: disable delayed refill when pausing rx")
Reported-by: Paolo Abeni <pabeni@redhat.com>
Closes: https://lore.kernel.org/526b5396-459d-4d02-8635-a222d07b46d7@redhat.com
Cc: stable@vger.kernel.org
Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://patch.msgid.link/20260106150438.7425-2-minhquangbui99@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>