virtio_net: use non-reentrant workqueue.
Michael S. Tsirkin also noticed that we could run the refill work
multiple CPUs: if we kick off a refill on one CPU and then on another,
they would both manipulate the queue at the same time (they use
napi_disable to avoid racing against the receive handler itself).
Tejun points out that this is what the WQ_NON_REENTRANT flag is for,
and that there is a convenient system kthread we can use.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 07ca150..2055386 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -508,7 +508,7 @@
/* In theory, this can happen: if we don't get any buffers in
* we will *never* try to fill again. */
if (still_empty)
- schedule_delayed_work(&vi->refill, HZ/2);
+ queue_delayed_work(system_nrt_wq, &vi->refill, HZ/2);
}
static int virtnet_poll(struct napi_struct *napi, int budget)
@@ -527,7 +527,7 @@
if (vi->num < vi->max / 2) {
if (!try_fill_recv(vi, GFP_ATOMIC))
- schedule_delayed_work(&vi->refill, 0);
+ queue_delayed_work(system_nrt_wq, &vi->refill, 0);
}
/* Out of packets? */
@@ -729,7 +729,7 @@
/* Make sure we have some buffers: if oom use wq. */
if (!try_fill_recv(vi, GFP_KERNEL))
- schedule_delayed_work(&vi->refill, 0);
+ queue_delayed_work(system_nrt_wq, &vi->refill, 0);
virtnet_napi_enable(vi);
return 0;
