[PATCH 5.4 37/51] hv_netvsc: Register VF in netvsc_probe if NET_DEVICE_REGISTER missed

Sasha Levin
2024-03-13T17:02:55Z

From: Shradha Gupta <shradhagupta@linux.microsoft.com>

[ Upstream commit 9cae43da9867412f8bd09aee5c8a8dc5e8dc3dc2 ]

If hv_netvsc driver is unloaded and reloaded, the NET_DEVICE_REGISTER
handler cannot perform VF register successfully as the register call
is received before netvsc_probe is finished. This is because we
register register_netdevice_notifier() very early( even before
vmbus_driver_register()).
To fix this, we try to register each such matching VF( if it is visible
as a netdevice) at the end of netvsc_probe.

Cc: stable@vger.kernel.org
Fixes: 85520856466e ("hv_netvsc: Fix race of register_netdevice_notifier and VF register")
Suggested-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/hyperv/netvsc_drv.c | 82 +++++++++++++++++++++++++--------
1 file changed, 62 insertions(+), 20 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 880c3f69c9c10..e42102a1de41f 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -43,6 +43,10 @@
#define LINKCHANGE_INT (2 * HZ)
#define VF_TAKEOVER_INT (HZ / 10)

+/* Macros to define the context of vf registration */
+#define VF_REG_IN_PROBE 1
+#define VF_REG_IN_NOTIFIER 2
+
static unsigned int ring_size __ro_after_init = 128;
module_param(ring_size, uint, 0444);
MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
@@ -2037,7 +2041,7 @@ static rx_handler_result_t netvsc_vf_handle_frame(struct sk_buff **pskb)
}

static int netvsc_vf_join(struct net_device *vf_netdev,
- struct net_device *ndev)
+ struct net_device *ndev, int context)
{
struct net_device_context *ndev_ctx = netdev_priv(ndev);
int ret;
@@ -2060,7 +2064,11 @@ static int netvsc_vf_join(struct net_device *vf_netdev,
goto upper_link_failed;
}

- schedule_delayed_work(&ndev_ctx->vf_takeover, VF_TAKEOVER_INT);
+ /* If this registration is called from probe context vf_takeover
+ * is taken care of later in probe itself.
+ */
+ if (context == VF_REG_IN_NOTIFIER)
+ schedule_delayed_work(&ndev_ctx->vf_takeover, VF_TAKEOVER_INT);

call_netdevice_notifiers(NETDEV_JOIN, vf_netdev);

@@ -2198,7 +2206,7 @@ static int netvsc_prepare_bonding(struct net_device *vf_netdev)
return NOTIFY_DONE;
}

-static int netvsc_register_vf(struct net_device *vf_netdev)
+static int netvsc_register_vf(struct net_device *vf_netdev, int context)
{
struct net_device_context *net_device_ctx;
struct netvsc_device *netvsc_dev;
@@ -2237,7 +2245,7 @@ static int netvsc_register_vf(struct net_device *vf_netdev)

netdev_info(ndev, "VF registering: %s\n", vf_netdev->name);

- if (netvsc_vf_join(vf_netdev, ndev) != 0)
+ if (netvsc_vf_join(vf_netdev, ndev, context) != 0)
return NOTIFY_DONE;

dev_hold(vf_netdev);
@@ -2301,10 +2309,31 @@ static int netvsc_unregister_vf(struct net_device *vf_netdev)
return NOTIFY_OK;
}

+static int check_dev_is_matching_vf(struct net_device *event_ndev)
+{
+ /* Skip NetVSC interfaces */
+ if (event_ndev->netdev_ops == &device_ops)
+ return -ENODEV;
+
+ /* Avoid non-Ethernet type devices */
+ if (event_ndev->type != ARPHRD_ETHER)
+ return -ENODEV;
+
+ /* Avoid Vlan dev with same MAC registering as VF */
+ if (is_vlan_dev(event_ndev))
+ return -ENODEV;
+
+ /* Avoid Bonding master dev with same MAC registering as VF */
+ if (netif_is_bond_master(event_ndev))
+ return -ENODEV;
+
+ return 0;
+}
+
static int netvsc_probe(struct hv_device *dev,
const struct hv_vmbus_device_id *dev_id)
{
- struct net_device *net = NULL;
+ struct net_device *net = NULL, *vf_netdev;
struct net_device_context *net_device_ctx;
struct netvsc_device_info *device_info = NULL;
struct netvsc_device *nvdev;
@@ -2405,6 +2434,30 @@ static int netvsc_probe(struct hv_device *dev,
}

list_add(&net_device_ctx->list, &netvsc_dev_list);
+
+ /* When the hv_netvsc driver is unloaded and reloaded, the
+ * NET_DEVICE_REGISTER for the vf device is replayed before probe
+ * is complete. This is because register_netdevice_notifier() gets
+ * registered before vmbus_driver_register() so that callback func
+ * is set before probe and we don't miss events like NETDEV_POST_INIT
+ * So, in this section we try to register the matching vf device that
+ * is present as a netdevice, knowing that its register call is not
+ * processed in the netvsc_netdev_notifier(as probing is progress and
+ * get_netvsc_byslot fails).
+ */
+ for_each_netdev(dev_net(net), vf_netdev) {
+ ret = check_dev_is_matching_vf(vf_netdev);
+ if (ret != 0)
+ continue;
+
+ if (net != get_netvsc_byslot(vf_netdev))
+ continue;
+
+ netvsc_prepare_bonding(vf_netdev);
+ netvsc_register_vf(vf_netdev, VF_REG_IN_PROBE);
+ __netvsc_vf_setup(net, vf_netdev);
+ break;
+ }
rtnl_unlock();

kfree(device_info);
@@ -2497,28 +2550,17 @@ static int netvsc_netdev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
+ int ret = 0;

- /* Skip our own events */
- if (event_dev->netdev_ops == &device_ops)
- return NOTIFY_DONE;
-
- /* Avoid non-Ethernet type devices */
- if (event_dev->type != ARPHRD_ETHER)
- return NOTIFY_DONE;
-
- /* Avoid Vlan dev with same MAC registering as VF */
- if (is_vlan_dev(event_dev))
- return NOTIFY_DONE;
-
- /* Avoid Bonding master dev with same MAC registering as VF */
- if (netif_is_bond_master(event_dev))
+ ret = check_dev_is_matching_vf(event_dev);
+ if (ret != 0)
return NOTIFY_DONE;

switch (event) {
case NETDEV_POST_INIT:
return netvsc_prepare_bonding(event_dev);
case NETDEV_REGISTER:
- return netvsc_register_vf(event_dev);
+ return netvsc_register_vf(event_dev, VF_REG_IN_NOTIFIER);
case NETDEV_UNREGISTER:
return netvsc_unregister_vf(event_dev);
case NETDEV_UP:
--
2.43.0