3 files changed, 70 insertions, 2 deletions

diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 403508a52e17..71c50751b5a6 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -859,10 +859,72 @@ static ssize_t nvmet_subsys_attr_serial_store(struct config_item *item,
 }
 CONFIGFS_ATTR(nvmet_subsys_, attr_serial);
 
+static ssize_t nvmet_subsys_attr_cntlid_min_show(struct config_item *item,
+						 char *page)
+{
+	return snprintf(page, PAGE_SIZE, "%u\n", to_subsys(item)->cntlid_min);
+}
+
+static ssize_t nvmet_subsys_attr_cntlid_min_store(struct config_item *item,
+						  const char *page, size_t cnt)
+{
+	u16 cntlid_min;
+
+	if (sscanf(page, "%hu\n", &cntlid_min) != 1)
+		return -EINVAL;
+
+	if (cntlid_min == 0)
+		return -EINVAL;
+
+	down_write(&nvmet_config_sem);
+	if (cntlid_min >= to_subsys(item)->cntlid_max)
+		goto out_unlock;
+	to_subsys(item)->cntlid_min = cntlid_min;
+	up_write(&nvmet_config_sem);
+	return cnt;
+
+out_unlock:
+	up_write(&nvmet_config_sem);
+	return -EINVAL;
+}
+CONFIGFS_ATTR(nvmet_subsys_, attr_cntlid_min);
+
+static ssize_t nvmet_subsys_attr_cntlid_max_show(struct config_item *item,
+						 char *page)
+{
+	return snprintf(page, PAGE_SIZE, "%u\n", to_subsys(item)->cntlid_max);
+}
+
+static ssize_t nvmet_subsys_attr_cntlid_max_store(struct config_item *item,
+						  const char *page, size_t cnt)
+{
+	u16 cntlid_max;
+
+	if (sscanf(page, "%hu\n", &cntlid_max) != 1)
+		return -EINVAL;
+
+	if (cntlid_max == 0)
+		return -EINVAL;
+
+	down_write(&nvmet_config_sem);
+	if (cntlid_max <= to_subsys(item)->cntlid_min)
+		goto out_unlock;
+	to_subsys(item)->cntlid_max = cntlid_max;
+	up_write(&nvmet_config_sem);
+	return cnt;
+
+out_unlock:
+	up_write(&nvmet_config_sem);
+	return -EINVAL;
+}
+CONFIGFS_ATTR(nvmet_subsys_, attr_cntlid_max);
+
 static struct configfs_attribute *nvmet_subsys_attrs[] = {
 	&nvmet_subsys_attr_attr_allow_any_host,
 	&nvmet_subsys_attr_attr_version,
 	&nvmet_subsys_attr_attr_serial,
+	&nvmet_subsys_attr_attr_cntlid_min,
+	&nvmet_subsys_attr_attr_cntlid_max,
 	NULL,
 };
 
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 576de773b4db..48080c948692 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1289,8 +1289,11 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
 	if (!ctrl->sqs)
 		goto out_free_cqs;
 
+	if (subsys->cntlid_min > subsys->cntlid_max)
+		goto out_free_cqs;
+
 	ret = ida_simple_get(&cntlid_ida,
-			     NVME_CNTLID_MIN, NVME_CNTLID_MAX,
+			     subsys->cntlid_min, subsys->cntlid_max,
 			     GFP_KERNEL);
 	if (ret < 0) {
 		status = NVME_SC_CONNECT_CTRL_BUSY | NVME_SC_DNR;
@@ -1438,7 +1441,8 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
 		kfree(subsys);
 		return ERR_PTR(-ENOMEM);
 	}
-
+	subsys->cntlid_min = NVME_CNTLID_MIN;
+	subsys->cntlid_max = NVME_CNTLID_MAX;
 	kref_init(&subsys->ref);
 
 	mutex_init(&subsys->lock);
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index eda28b22a2c8..c2d518fb1789 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -211,6 +211,8 @@ struct nvmet_subsys {
 	struct list_head	namespaces;
 	unsigned int		nr_namespaces;
 	unsigned int		max_nsid;
+	u16			cntlid_min;
+	u16			cntlid_max;
 
 	struct list_head	ctrls;