RDMA: Lift ibdev_to_node from rds to common code

stable inclusion
from stable-5.10.19
commit 225d207da2e1169aee30faaa71bd7cf70c7277a3
bugzilla: 50607

--------------------------------

commit 8ecfca68 upstream.

Lift the ibdev_to_node from rds to common code and document it.

Link: https://lore.kernel.org/r/20201106181941.1878556-4-hch@lst.deSigned-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
Cc: Krishnamraju Eraparaju <krishna2@chelsio.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

include/rdma/ib_verbs.h

@@ -4642,6 +4642,19 @@ static inline struct ib_device *rdma_device_to_ibdev(struct device *device)
 	return coredev->owner;
 }
 
+/**
+ * ibdev_to_node - return the NUMA node for a given ib_device
+ * @dev:	device to get the NUMA node for.
+ */
+static inline int ibdev_to_node(struct ib_device *ibdev)
+{
+	struct device *parent = ibdev->dev.parent;
+
+	if (!parent)
+		return NUMA_NO_NODE;
+	return dev_to_node(parent);
+}
+
 /**
  * rdma_device_to_drv_device - Helper macro to reach back to driver's
  *			       ib_device holder structure from device pointer.

net/rds/ib.h

@@ -264,13 +264,6 @@ struct rds_ib_device {
 	int			*vector_load;
 };
 
-static inline int ibdev_to_node(struct ib_device *ibdev)
-{
-	struct device *parent;
-
-	parent = ibdev->dev.parent;
-	return parent ? dev_to_node(parent) : NUMA_NO_NODE;
-}
 #define rdsibdev_to_node(rdsibdev) ibdev_to_node(rdsibdev->dev)
 
 /* bits for i_ack_flags */