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

[Kamaljit Singh]

Added capability to connect to an administrative controller by
preventing ioq creation for admin-controllers. Also prevent ioq creation
for discovery-controllers as the spec prohibits them.

* Added nvme_admin_ctrl() to check for an administrative controller

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

* 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>
---
 drivers/nvme/host/core.c    | 25 +++++++++++++------------
 drivers/nvme/host/fabrics.h |  5 +++++
 drivers/nvme/host/nvme.h    |  5 +++++
 drivers/nvme/host/rdma.c    | 11 +++++++++++
 drivers/nvme/host/tcp.c     | 11 +++++++++++
 5 files changed, 45 insertions(+), 12 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 60537c9224bf..417893c4e8e8 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2800,11 +2800,6 @@ static struct nvme_subsystem *__nvme_find_get_subsystem(const char *subsysnqn)
 	return NULL;
 }
 
-static inline bool nvme_discovery_ctrl(struct nvme_ctrl *ctrl)
-{
-	return ctrl->opts && ctrl->opts->discovery_nqn;
-}
-
 static bool nvme_validate_cntlid(struct nvme_subsystem *subsys,
 		struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 {
@@ -2825,7 +2820,7 @@ static bool nvme_validate_cntlid(struct nvme_subsystem *subsys,
 		}
 
 		if ((id->cmic & NVME_CTRL_CMIC_MULTI_CTRL) ||
-		    nvme_discovery_ctrl(ctrl))
+		    nvmf_discovery_ctrl(ctrl))
 			continue;
 
 		dev_err(ctrl->device,
@@ -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);
+	}
+
 	subsys->awupf = le16_to_cpu(id->awupf);
 	nvme_mpath_default_iopolicy(subsys);
 
@@ -3093,20 +3094,20 @@ static int nvme_check_ctrl_fabric_info(struct nvme_ctrl *ctrl, struct nvme_id_ct
 		return -EINVAL;
 	}
 
-	if (!nvme_discovery_ctrl(ctrl) && !ctrl->kas) {
+	if (!nvmf_discovery_ctrl(ctrl) && !ctrl->kas) {
 		dev_err(ctrl->device,
 			"keep-alive support is mandatory for fabrics\n");
 		return -EINVAL;
 	}
 
-	if (!nvme_discovery_ctrl(ctrl) && ctrl->ioccsz < 4) {
+	if (!nvmf_discovery_ctrl(ctrl) && ctrl->ioccsz < 4) {
 		dev_err(ctrl->device,
 			"I/O queue command capsule supported size %d < 4\n",
 			ctrl->ioccsz);
 		return -EINVAL;
 	}
 
-	if (!nvme_discovery_ctrl(ctrl) && ctrl->iorcsz < 1) {
+	if (!nvmf_discovery_ctrl(ctrl) && ctrl->iorcsz < 1) {
 		dev_err(ctrl->device,
 			"I/O queue response capsule supported size %d < 1\n",
 			ctrl->iorcsz);
@@ -3290,7 +3291,7 @@ int nvme_init_ctrl_finish(struct nvme_ctrl *ctrl, bool was_suspended)
 
 	nvme_configure_opal(ctrl, was_suspended);
 
-	if (!ctrl->identified && !nvme_discovery_ctrl(ctrl)) {
+	if (!ctrl->identified && !nvmf_discovery_ctrl(ctrl) && !nvme_admin_ctrl(ctrl)) {
 		/*
 		 * Do not return errors unless we are in a controller reset,
 		 * the controller works perfectly fine without hwmon.
@@ -4492,7 +4493,7 @@ void nvme_start_ctrl(struct nvme_ctrl *ctrl)
 	 * checking that they started once before, hence are reconnecting back.
 	 */
 	if (test_bit(NVME_CTRL_STARTED_ONCE, &ctrl->flags) &&
-	    nvme_discovery_ctrl(ctrl))
+	    nvmf_discovery_ctrl(ctrl))
 		nvme_change_uevent(ctrl, "NVME_EVENT=rediscover");
 
 	if (ctrl->queue_count > 1) {
diff --git a/drivers/nvme/host/fabrics.h b/drivers/nvme/host/fabrics.h
index 06cc54851b1b..679cf5282cee 100644
--- a/drivers/nvme/host/fabrics.h
+++ b/drivers/nvme/host/fabrics.h
@@ -181,6 +181,11 @@ struct nvmf_transport_ops {
 					struct nvmf_ctrl_options *opts);
 };
 
+static inline bool nvmf_discovery_ctrl(struct nvme_ctrl *ctrl)
+{
+	return ctrl->opts && ctrl->opts->discovery_nqn;
+}
+
 static inline bool
 nvmf_ctlr_matches_baseopts(struct nvme_ctrl *ctrl,
 			struct nvmf_ctrl_options *opts)
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 7b87763e2f8a..7c2d896a754c 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -1135,6 +1135,11 @@ struct nvme_ctrl *nvme_ctrl_from_file(struct file *file);
 struct nvme_ns *nvme_find_get_ns(struct nvme_ctrl *ctrl, unsigned nsid);
 void nvme_put_ns(struct nvme_ns *ns);
 
+static inline bool nvme_admin_ctrl(struct nvme_ctrl *ctrl)
+{
+	return (ctrl->cntrltype == NVME_CTRL_ADMIN);
+}
+
 static inline bool nvme_multi_css(struct nvme_ctrl *ctrl)
 {
 	return (ctrl->ctrl_config & NVME_CC_CSS_MASK) == NVME_CC_CSS_CSI;
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;
+	}
+
 	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",
-- 
2.43.0