Patch-mainline: v6.4-rc1

Git-commit: f8bb5104394560e29017c25bcade4c6b7aabd108

References: git-fixes

From: Wenliang Wang <wangwenliang.1995@bytedance.com>

Date: Thu, 4 May 2023 10:27:06 +0800

Subject: [PATCH] virtio_net: suppress cpu stall when free_unused_bufs

For multi-queue and large ring-size use case, the following error

occurred when free_unused_bufs:

rcu: INFO: rcu_sched self-detected stall on CPU.

Fixes: 986a4f4d452d ("virtio_net: multiqueue support")

Signed-off-by: Wenliang Wang <wangwenliang.1995@bytedance.com>

Acked-by: Michael S. Tsirkin <mst@redhat.com>

Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Juergen Gross <jgross@suse.com>

---

 drivers/net/virtio_net.c | 2 ++

 1 file changed, 2 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c

index 8d8038538fc4..a12ae26db0e2 100644

--- a/drivers/net/virtio_net.c

+++ b/drivers/net/virtio_net.c

@@ -3560,12 +3560,14 @@ static void free_unused_bufs(struct virtnet_info *vi)

 		struct virtqueue *vq = vi->sq[i].vq;

 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)

 			virtnet_sq_free_unused_buf(vq, buf);

+		cond_resched();

 	}

 	for (i = 0; i < vi->max_queue_pairs; i++) {

 		struct virtqueue *vq = vi->rq[i].vq;

 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)

 			virtnet_rq_free_unused_buf(vq, buf);

+		cond_resched();

 	}

 }

-- 

2.35.3