Commit e715b873 authored Jul 21, 2025 by Kamaljit Singh Committed by Christoph Hellwig Jul 31, 2025

nvme: add capability to connect to an administrative controller



Add capability to connect to an administrative controller by
preventing ioq creation for admin-controllers.

Add a nvme_admin_ctrl() to check if a controller's CNTRLTYPE indicates
that it is an administrative controller and override ctrl->queue_count to
1 for admin controllers, so that only the admin queue and no I/O queues
are created for an administrative controller.  This override is done in
nvme_init_ctrl_finish() after ctrl->cntrltype has been initialized in
nvme_init_identify() so nvme_admin_ctrl() will work correctly.
Doing this override in generic code (nvme_init_ctrl_finish) makes it
transport agnostic and will work properly for nvme/tcp as well as for
nvme/rdma.

Suggested-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Kamaljit Singh <kamaljit.singh1@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

parent c71fc0f4

drivers/nvme/host/core.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -3158,6 +3158,11 @@ static inline bool nvme_discovery_ctrl(struct nvme_ctrl *ctrl)
		return ctrl->opts && ctrl->opts->discovery_nqn;
		}

		static inline bool nvme_admin_ctrl(struct nvme_ctrl *ctrl)
		{
		return ctrl->cntrltype == NVME_CTRL_ADMIN;
		}

		static bool nvme_validate_cntlid(struct nvme_subsystem *subsys,
		struct nvme_ctrl ctrl, struct nvme_id_ctrl id)
		{
		@@ -3670,6 +3675,17 @@ int nvme_init_ctrl_finish(struct nvme_ctrl *ctrl, bool was_suspended)
		if (ret)
		return ret;

		if (nvme_admin_ctrl(ctrl)) {
		/*
		* An admin controller has one admin queue, but no I/O queues.
		* Override queue_count so it only creates an admin queue.
		*/
		dev_dbg(ctrl->device,
		"Subsystem %s is an administrative controller",
		ctrl->subsys->subnqn);
		ctrl->queue_count = 1;
		}

		ret = nvme_configure_apst(ctrl);
		if (ret < 0)
		return ret;