Add an new RPC bdev_nvme_get_io_paths to query all active I/O paths.
One io_path belongs to One nvme_bdev_channel.
Each nvme_bdev_channel is associated with one nvme_bdev.
If the RPC bdev_nvme_get_io_paths has a bdev name as a parameter
it can use spdk_for_each_channel() simply for the corresponding
nvme_bdev.
However, users will want to know I/O paths of all nvme_bdevs like
the RPC bdev_get_bdevs.
One io_path has one nvme_qpair. One nvme_qpair belongs to one
nvme_poll_group. By relying on these relationships, the RPC
bdev_nvme_get_io_paths traverses all nvme_poll_groups by using
spdk_for_each_channel() to g_bdev_nvme_ctrlrs.
The RPC bdev_nvme_get_io_paths has two modes, display all or
the specified NVMe bdev's active I/O paths.
The specified bdev name is used just for comparison and empty
array is returned if no matched io_path is found.
Signed-off-by: Shuhei Matsumoto <smatsumoto@nvidia.com>
Change-Id: I4a0dbf3ef7aaa9a7b7345fc03dc493cc6d37bc99
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/12146
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>