9p/trans_virtio: Remove sysfs file on probe failure

This ensures we don't leak the sysfs file if we failed to
allocate chan->vc_wq during probe.

Link: http://lkml.kernel.org/r/20210517083557.172-1-xieyongji@bytedance.com
Fixes: 86c8437 ("net/9p: Add sysfs mount_tag file for virtio 9P device")
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>

net/9p/trans_virtio.c

@@ -610,7 +610,7 @@ static int p9_virtio_probe(struct virtio_device *vdev)
 	chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
 	if (!chan->vc_wq) {
 		err = -ENOMEM;
-		goto out_free_tag;
+		goto out_remove_file;
 	}
 	init_waitqueue_head(chan->vc_wq);
 	chan->ring_bufs_avail = 1;
@@ -628,6 +628,8 @@ static int p9_virtio_probe(struct virtio_device *vdev)
 
 	return 0;
 
+out_remove_file:
+	sysfs_remove_file(&vdev->dev.kobj, &dev_attr_mount_tag.attr);
 out_free_tag:
 	kfree(tag);
 out_free_vq: