Commit 54d4434d authored by Paolo Abeni's avatar Paolo Abeni
Browse files

Merge branch 'hv_netvsc-fix-race-of-netvsc-vf-register-and-slave-bit' 

Haiyang Zhang says:

====================
hv_netvsc: fix race of netvsc, VF register, and slave bit

There are some races between netvsc probe, set notifier, VF register,
and slave bit setting.
This patch set fixes them.
====================

Link: https://lore.kernel.org/r/1700411023-14317-1-git-send-email-haiyangz@microsoft.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parents c0e29262 c807d6cd

drivers/net/hyperv/netvsc_drv.c

+45 −21
Original line number Diff line number Diff line
@@ -2206,9 +2206,6 @@ static int netvsc_vf_join(struct net_device *vf_netdev, 
		goto upper_link_failed;

	}



	/* set slave flag before open to prevent IPv6 addrconf */

	vf_netdev->flags |= IFF_SLAVE;



	schedule_delayed_work(&ndev_ctx->vf_takeover, VF_TAKEOVER_INT);



	call_netdevice_notifiers(NETDEV_JOIN, vf_netdev);
@@ -2315,23 +2312,38 @@ static struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev) 


	}



	/* Fallback path to check synthetic vf with

	 * help of mac addr

	/* Fallback path to check synthetic vf with help of mac addr.

	 * Because this function can be called before vf_netdev is

	 * initialized (NETDEV_POST_INIT) when its perm_addr has not been copied

	 * from dev_addr, also try to match to its dev_addr.

	 * Note: On Hyper-V and Azure, it's not possible to set a MAC address

	 * on a VF that matches to the MAC of a unrelated NETVSC device.

	 */

	list_for_each_entry(ndev_ctx, &netvsc_dev_list, list) {

		ndev = hv_get_drvdata(ndev_ctx->device_ctx);

		if (ether_addr_equal(vf_netdev->perm_addr, ndev->perm_addr)) {

			netdev_notice(vf_netdev,

				      "falling back to mac addr based matching\n");

		if (ether_addr_equal(vf_netdev->perm_addr, ndev->perm_addr) ||

		    ether_addr_equal(vf_netdev->dev_addr, ndev->perm_addr))

			return ndev;

	}

	}



	netdev_notice(vf_netdev,

		      "no netdev found for vf serial:%u\n", serial);

	return NULL;

}



static int netvsc_prepare_bonding(struct net_device *vf_netdev)

{

	struct net_device *ndev;



	ndev = get_netvsc_byslot(vf_netdev);

	if (!ndev)

		return NOTIFY_DONE;



	/* set slave flag before open to prevent IPv6 addrconf */

	vf_netdev->flags |= IFF_SLAVE;

	return NOTIFY_DONE;

}



static int netvsc_register_vf(struct net_device *vf_netdev)

{

	struct net_device_context *net_device_ctx;
@@ -2531,15 +2543,6 @@ static int netvsc_probe(struct hv_device *dev, 
		goto devinfo_failed;

	}



	nvdev = rndis_filter_device_add(dev, device_info);

	if (IS_ERR(nvdev)) {

		ret = PTR_ERR(nvdev);

		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);

		goto rndis_failed;

	}



	eth_hw_addr_set(net, device_info->mac_adr);



	/* We must get rtnl lock before scheduling nvdev->subchan_work,

	 * otherwise netvsc_subchan_work() can get rtnl lock first and wait

	 * all subchannels to show up, but that may not happen because
@@ -2547,9 +2550,23 @@ static int netvsc_probe(struct hv_device *dev, 
	 * -> ... -> device_add() -> ... -> __device_attach() can't get

	 * the device lock, so all the subchannels can't be processed --

	 * finally netvsc_subchan_work() hangs forever.

	 *

	 * The rtnl lock also needs to be held before rndis_filter_device_add()

	 * which advertises nvsp_2_vsc_capability / sriov bit, and triggers

	 * VF NIC offering and registering. If VF NIC finished register_netdev()

	 * earlier it may cause name based config failure.

	 */

	rtnl_lock();



	nvdev = rndis_filter_device_add(dev, device_info);

	if (IS_ERR(nvdev)) {

		ret = PTR_ERR(nvdev);

		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);

		goto rndis_failed;

	}



	eth_hw_addr_set(net, device_info->mac_adr);



	if (nvdev->num_chn > 1)

		schedule_work(&nvdev->subchan_work);
@@ -2586,9 +2603,9 @@ static int netvsc_probe(struct hv_device *dev, 
	return 0;



register_failed:

	rtnl_unlock();

	rndis_filter_device_remove(dev, nvdev);

rndis_failed:

	rtnl_unlock();

	netvsc_devinfo_put(device_info);

devinfo_failed:

	free_percpu(net_device_ctx->vf_stats);
@@ -2753,6 +2770,8 @@ static int netvsc_netdev_event(struct notifier_block *this, 
		return NOTIFY_DONE;



	switch (event) {

	case NETDEV_POST_INIT:

		return netvsc_prepare_bonding(event_dev);

	case NETDEV_REGISTER:

		return netvsc_register_vf(event_dev);

	case NETDEV_UNREGISTER:
@@ -2788,12 +2807,17 @@ static int __init netvsc_drv_init(void) 
	}

	netvsc_ring_bytes = ring_size * PAGE_SIZE;



	register_netdevice_notifier(&netvsc_netdev_notifier);



	ret = vmbus_driver_register(&netvsc_drv);

	if (ret)

		return ret;

		goto err_vmbus_reg;



	register_netdevice_notifier(&netvsc_netdev_notifier);

	return 0;



err_vmbus_reg:

	unregister_netdevice_notifier(&netvsc_netdev_notifier);

	return ret;

}



MODULE_LICENSE("GPL");