RDMA: Lift ibdev_to_node from rds to common code

commit 8ecfca68dc4cbee1272a0161e3f2fb9387dc6930 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.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Krishnamraju Eraparaju <krishna2@chelsio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed