Re: [PATCH v1 1/1] nvme: add admin controller support. prohibit ioq creation for admin & disco ctrlrs

From: Damien Le Moal
Date: Fri Mar 28 2025 - 18:09:22 EST


On 2025/03/28 14:36, Kamaljit Singh wrote:
> Added capability to connect to an administrative controller by

s/Added/Add

> preventing ioq creation for admin-controllers. Also prevent ioq creation
> for discovery-controllers as the spec prohibits them.

This second part should be a different (preparatory) patch.

>
> * Added nvme_admin_ctrl() to check for an administrative controller

s/Added/Add
And this should be a different preparatory patch.

>
> * Renamed nvme_discovery_ctrl() to nvmf_discovery_ctrl() as discovery is
> more relevant to fabrics

I do not think that is necessary since this is testing the controller type,
which may be limited to fabrics or not.

> * Similar to a discovery ctrl, prevent an admin-ctrl from getting a
> smart log (LID=2). LID 2 is optional for admin controllers but in the
> future when we add support for the newly added LID=0 (supported log
> pages), we can make GLP accesses smarter by basing such calls on
> response from LID=0 reads.
>
> Signed-off-by: Kamaljit Singh <kamaljit.singh1@xxxxxxx>

[...]

> @@ -2863,13 +2858,19 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
> else
> subsys->subtype = NVME_NQN_NVME;
>
> - if (nvme_discovery_ctrl(ctrl) && subsys->subtype != NVME_NQN_DISC) {
> + if (nvmf_discovery_ctrl(ctrl) && subsys->subtype != NVME_NQN_DISC) {
> dev_err(ctrl->device,
> "Subsystem %s is not a discovery controller",
> subsys->subnqn);
> kfree(subsys);
> return -EINVAL;
> }
> + if (nvme_admin_ctrl(ctrl)) {
> + dev_info(ctrl->device,
> + "Subsystem %s is an administrative controller",
> + subsys->subnqn);
> + }

Is this really necessary ? In any case, please remove the curly brackets.

[...]

> diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
> index 299e3c19df9d..0f3150411bd5 100644
> --- a/drivers/nvme/host/rdma.c
> +++ b/drivers/nvme/host/rdma.c
> @@ -1030,6 +1030,17 @@ static int nvme_rdma_setup_ctrl(struct nvme_rdma_ctrl *ctrl, bool new)
> goto destroy_admin;
> }
>
> + /* An admin or discovery controller has one admin queue, but no I/O queues */
> + if (nvme_admin_ctrl(&ctrl->ctrl) || nvmf_discovery_ctrl(&ctrl->ctrl)) {
> + ctrl->ctrl.queue_count = 1;
> + } else if (ctrl->ctrl.queue_count < 2) {
> + /* I/O controller with no I/O queues is not allowed */
> + ret = -EOPNOTSUPP;
> + dev_err(ctrl->ctrl.device,
> + "I/O controller doesn't allow zero I/O queues!\n");
> + goto destroy_admin;
> + }

This is identical to the change for tcp, so maybe make this a helper function ?

> +
> if (ctrl->ctrl.opts->queue_size > ctrl->ctrl.sqsize + 1) {
> dev_warn(ctrl->ctrl.device,
> "queue_size %zu > ctrl sqsize %u, clamping down\n",
> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
> index 644f84284b6f..3fe2f617bfd5 100644
> --- a/drivers/nvme/host/tcp.c
> +++ b/drivers/nvme/host/tcp.c
> @@ -2199,6 +2199,17 @@ static int nvme_tcp_setup_ctrl(struct nvme_ctrl *ctrl, bool new)
> goto destroy_admin;
> }
>
> + /* An admin or discovery controller has one admin queue, but no I/O queues */
> + if (nvme_admin_ctrl(ctrl) || nvmf_discovery_ctrl(ctrl)) {
> + ctrl->queue_count = 1;
> + } else if (ctrl->queue_count < 2) {
> + /* I/O controller with no I/O queues is not allowed */
> + ret = -EOPNOTSUPP;
> + dev_err(ctrl->device,
> + "I/O controller doesn't allow zero I/O queues!\n");
> + goto destroy_admin;
> + }
> +
> if (opts->queue_size > ctrl->sqsize + 1)
> dev_warn(ctrl->device,
> "queue_size %zu > ctrl sqsize %u, clamping down\n",

--
Damien Le Moal
Western Digital Research