virtio-net: correctly delete napi hash

We don't delete napi from hash list during module exit. This will
cause the following panic when doing module load and unload:

BUG: unable to handle kernel paging request at 0000004e00000075
IP: [<ffffffff816bd01b>] napi_hash_add+0x6b/0xf0
PGD 3c5d5067 PUD 0
Oops: 0000 [#1] SMP
...
Call Trace:
[<ffffffffa0a5bfb7>] init_vqs+0x107/0x490 [virtio_net]
[<ffffffffa0a5c9f2>] virtnet_probe+0x562/0x791815639d880be [virtio_net]
[<ffffffff8139e667>] virtio_dev_probe+0x137/0x200
[<ffffffff814c7f2a>] driver_probe_device+0x7a/0x250
[<ffffffff814c81d3>] __driver_attach+0x93/0xa0
[<ffffffff814c8140>] ? __device_attach+0x40/0x40
[<ffffffff814c6053>] bus_for_each_dev+0x63/0xa0
[<ffffffff814c7a79>] driver_attach+0x19/0x20
[<ffffffff814c76f0>] bus_add_driver+0x170/0x220
[<ffffffffa0a60000>] ? 0xffffffffa0a60000
[<ffffffff814c894f>] driver_register+0x5f/0xf0
[<ffffffff8139e41b>] register_virtio_driver+0x1b/0x30
[<ffffffffa0a60010>] virtio_net_driver_init+0x10/0x12 [virtio_net]

This patch fixes this by doing this in virtnet_free_queues(). And also
don't delete napi in virtnet_freeze() since it will call
virtnet_free_queues() which has already did this.

Fixes 91815639d880 ("virtio-net: rx busy polling support")
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 5 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f1ff3666f090..59b0e9754ae3 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1448,8 +1448,10 @@ static void virtnet_free_queues(struct virtnet_info *vi)
 {
         int i;
 
-        for (i = 0; i < vi->max_queue_pairs; i++)
+        for (i = 0; i < vi->max_queue_pairs; i++) {
+                napi_hash_del(&vi->rq[i].napi);
                 netif_napi_del(&vi->rq[i].napi);
+        }
 
         kfree(vi->rq);
         kfree(vi->sq);
@@ -1948,11 +1950,8 @@ static int virtnet_freeze(struct virtio_device *vdev)
         cancel_delayed_work_sync(&vi->refill);
 
         if (netif_running(vi->dev)) {
-                for (i = 0; i < vi->max_queue_pairs; i++) {
+                for (i = 0; i < vi->max_queue_pairs; i++)
                         napi_disable(&vi->rq[i].napi);
-                        napi_hash_del(&vi->rq[i].napi);
-                        netif_napi_del(&vi->rq[i].napi);
-                }
         }
 
         remove_vq_common(vi);