[SRU][N:linux-azure][PATCH 3/3] RDMA/mana_ib: Handle net event for pointing to the current netdev

[John Cabaj]

From: Long Li <longli at microsoft.com>

BugLink: https://bugs.launchpad.net/bugs/2119572

When running under Hyper-V, the master device to the RDMA device is always
bonded to this RDMA device. This is not user-configurable.

The master device can be unbind/bind from the kernel. During those events,
the RDMA device should set to the current netdev to reflect the change of
master device from those events.

Signed-off-by: Long Li <longli at microsoft.com>
Link: https://patch.msgid.link/1741821332-9392-2-git-send-email-longli@linuxonhyperv.com
Signed-off-by: Leon Romanovsky <leon at kernel.org>
(backported from commit bee35b7161aaaed9831e2f14876c374b9c566952)
[john-cabaj: context changes]
Signed-off-by: John Cabaj <john.cabaj at canonical.com>
---
 drivers/infiniband/hw/mana/device.c  | 46 ++++++++++++++++++++++++++--
 drivers/infiniband/hw/mana/mana_ib.h |  1 +
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mana/device.c b/drivers/infiniband/hw/mana/device.c
index d69204e00e4a..e2cc88baa46d 100644
--- a/drivers/infiniband/hw/mana/device.c
+++ b/drivers/infiniband/hw/mana/device.c
@@ -46,6 +46,38 @@ static const struct ib_device_ops mana_ib_dev_ops = {
 			   ib_ind_table),
 };
 
+static int mana_ib_netdev_event(struct notifier_block *this,
+				unsigned long event, void *ptr)
+{
+	struct mana_ib_dev *dev = container_of(this, struct mana_ib_dev, nb);
+	struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
+	struct gdma_context *gc = dev->gdma_dev->gdma_context;
+	struct mana_context *mc = gc->mana.driver_data;
+	struct net_device *ndev;
+
+	/* Only process events from our parent device */
+	if (event_dev != mc->ports[0])
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case NETDEV_CHANGEUPPER:
+		ndev = mana_get_primary_netdev(mc, 0, &dev->dev_tracker);
+		/*
+		 * RDMA core will setup GID based on updated netdev.
+		 * It's not possible to race with the core as rtnl lock is being
+		 * held.
+		 */
+		ib_device_set_netdev(&dev->ib_dev, ndev, 1);
+
+		/* mana_get_primary_netdev() returns ndev with refcount held */
+		netdev_put(ndev, &dev->dev_tracker);
+
+		return NOTIFY_OK;
+	default:
+		return NOTIFY_DONE;
+	}
+}
+
 static int mana_ib_probe(struct auxiliary_device *adev,
 			 const struct auxiliary_device_id *id)
 {
@@ -100,11 +132,19 @@ static int mana_ib_probe(struct auxiliary_device *adev,
 	}
 	dev->gdma_dev = &mdev->gdma_context->mana_ib;
 
+	dev->nb.notifier_call = mana_ib_netdev_event;
+	ret = register_netdevice_notifier(&dev->nb);
+	if (ret) {
+		ibdev_err(&dev->ib_dev, "Failed to register net notifier, %d",
+			  ret);
+		goto deregister_device;
+	}
+
 	ret = mana_ib_gd_query_adapter_caps(dev);
 	if (ret) {
 		ibdev_err(&dev->ib_dev, "Failed to query device caps, ret %d",
 			  ret);
-		goto deregister_device;
+		goto deregister_net_notifier;
 	}
 
 	ret = ib_register_device(&dev->ib_dev, "mana_%d",
@@ -116,6 +156,8 @@ static int mana_ib_probe(struct auxiliary_device *adev,
 
 	return 0;
 
+deregister_net_notifier:
+	unregister_netdevice_notifier(&dev->nb);
 deregister_device:
 	mana_gd_deregister_device(dev->gdma_dev);
 free_ib_device:
@@ -128,7 +170,7 @@ static void mana_ib_remove(struct auxiliary_device *adev)
 	struct mana_ib_dev *dev = dev_get_drvdata(&adev->dev);
 
 	ib_unregister_device(&dev->ib_dev);
-
+	unregister_netdevice_notifier(&dev->nb);
 	mana_gd_deregister_device(dev->gdma_dev);
 
 	ib_dealloc_device(&dev->ib_dev);
diff --git a/drivers/infiniband/hw/mana/mana_ib.h b/drivers/infiniband/hw/mana/mana_ib.h
index a056b51475ee..cf8a3cfdc8eb 100644
--- a/drivers/infiniband/hw/mana/mana_ib.h
+++ b/drivers/infiniband/hw/mana/mana_ib.h
@@ -56,6 +56,7 @@ struct mana_ib_dev {
 	struct gdma_dev *gdma_dev;
 	struct mana_ib_adapter_caps adapter_caps;
 	netdevice_tracker dev_tracker;
+	struct notifier_block nb;
 };
 
 struct mana_ib_wq {
-- 
2.43.0