[PATCH] RDMA/ipoib: print a message if only child interface is UP

[Jack Wang <jinpu.wang@ionos.com>]

When "enhanced IPoIB" enabled for CX-5 devices, it requires
the parent device to be UP, otherwise the child devices won't
work.[1]

This add a debug message to give admin a hint, if only child interface
is UP, but parent interface is not.

[1]https://lore.kernel.org/linux-rdma/CAMGffE=3YYxv9i7_qQr3-Uv-NGr-7VsnMk8DTjR0YbX1vJBzXQ@mail.gmail.com/T/#u
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
---
 drivers/infiniband/ulp/ipoib/ipoib_main.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index e16b40c09f82..782b792985b8 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -164,8 +164,12 @@ int ipoib_open(struct net_device *dev)
 			dev_change_flags(cpriv->dev, flags | IFF_UP, NULL);
 		}
 		up_read(&priv->vlan_rwsem);
-	}
+	} else if (priv->parent) {
+		struct ipoib_dev_priv *ppriv = ipoib_priv(priv->parent);
 
+		if (!test_bit(IPOIB_FLAG_ADMIN_UP, &ppriv->flags))
+			ipoib_dbg(priv, "parent deivce %s is not up, so child may be not functioning.\n", ((struct ipoib_dev_priv *) ppriv)->dev->name);
+	}
 	netif_start_queue(dev);
 
 	return 0;
-- 
2.25.1