From: Jason Gunthorpe <jgg@xxxxxxxxxxxx> This allows userspace to ask the kernel for information on a specific char device implemented under the RDMA subsytem. For instance the kernel can ask for details on the uverbs0 chardev related to the mlx5_0 device. The resulting information is enough for libibverbs/etc to connect to the device without having to rely on sysfs. By using netlink this also supports automatic module loading. When userspace requests for a chardev that is not yet loaded, the kernel will load it, bind it to the device, and then return back. For uverbs the DRIVER_ID is returned in the GET_CHARDEV response. This allows libibverbs to bind drivers by ID instead of using modalias, or worse, the device name. This also fixes the problem where siw and rxe devices cannot be renamed. Only three drivers do not support this mechanism because their probe in userspace is too complicated (hns, mthca, cxgb3). As only hns is a current product, it should be revised to support DRIVER_ID matching. While the kernel side is fairly simple, the userspace is big and needs some more time to test: https://github.com/linux-rdma/rdma-core/pull/539 Jason Gunthorpe (3): RDMA: Move rdma_node_type to uapi/ RDMA: Add NLDEV_GET_CHARDEV to allow char dev discovery and autoload RDMA: Report available cdevs through RDMA_NLDEV_CMD_GET_CHARDEV drivers/infiniband/core/core_priv.h | 9 ++ drivers/infiniband/core/device.c | 91 ++++++++++++++++++++ drivers/infiniband/core/nldev.c | 91 ++++++++++++++++++++ drivers/infiniband/core/ucma.c | 23 +++++ drivers/infiniband/core/user_mad.c | 51 ++++++++++- drivers/infiniband/core/uverbs_main.c | 32 ++++++- drivers/infiniband/core/verbs.c | 2 +- drivers/infiniband/hw/cxgb3/iwch_provider.c | 1 + drivers/infiniband/hw/hns/hns_roce_main.c | 1 + drivers/infiniband/hw/mthca/mthca_provider.c | 1 + include/rdma/ib_verbs.h | 18 ++-- include/rdma/rdma_netlink.h | 2 + include/uapi/rdma/rdma_netlink.h | 23 +++++ 13 files changed, 327 insertions(+), 18 deletions(-) -- 2.21.0
