Commit 95409e27 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Keith Busch
Browse files

nvmet: implement unique discovery NQN 



Unique discovery NQNs allow to differentiate between discovery
services from (typically physically separate) NVMe-oF subsystems.
This is required for establishing secured connections as otherwise
the credentials won't be unique and the integrity of the connection
cannot be guaranteed.
This patch adds a configfs attribute 'discovery_nqn' in the 'nvmet'
configfs directory to specify the unique discovery NQN.

Signed-off-by: default avatarHannes Reinecke <hare@kernel.org>
Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: default avatarKeith Busch <kbusch@kernel.org>
parent 0551ec93

drivers/nvme/target/configfs.c

+47 −0
Original line number Diff line number Diff line
@@ -1613,6 +1613,11 @@ static struct config_group *nvmet_subsys_make(struct config_group *group, 
		return ERR_PTR(-EINVAL);

	}



	if (sysfs_streq(name, nvmet_disc_subsys->subsysnqn)) {

		pr_err("can't create subsystem using unique discovery NQN\n");

		return ERR_PTR(-EINVAL);

	}



	subsys = nvmet_subsys_alloc(name, NVME_NQN_NVME);

	if (IS_ERR(subsys))

		return ERR_CAST(subsys);
@@ -2159,7 +2164,49 @@ static const struct config_item_type nvmet_hosts_type = { 


static struct config_group nvmet_hosts_group;



static ssize_t nvmet_root_discovery_nqn_show(struct config_item *item,

					     char *page)

{

	return snprintf(page, PAGE_SIZE, "%s\n", nvmet_disc_subsys->subsysnqn);

}



static ssize_t nvmet_root_discovery_nqn_store(struct config_item *item,

		const char *page, size_t count)

{

	struct list_head *entry;

	size_t len;



	len = strcspn(page, "\n");

	if (!len || len > NVMF_NQN_FIELD_LEN - 1)

		return -EINVAL;



	down_write(&nvmet_config_sem);

	list_for_each(entry, &nvmet_subsystems_group.cg_children) {

		struct config_item *item =

			container_of(entry, struct config_item, ci_entry);



		if (!strncmp(config_item_name(item), page, len)) {

			pr_err("duplicate NQN %s\n", config_item_name(item));

			up_write(&nvmet_config_sem);

			return -EINVAL;

		}

	}

	memset(nvmet_disc_subsys->subsysnqn, 0, NVMF_NQN_FIELD_LEN);

	memcpy(nvmet_disc_subsys->subsysnqn, page, len);

	up_write(&nvmet_config_sem);



	return len;

}



CONFIGFS_ATTR(nvmet_root_, discovery_nqn);



static struct configfs_attribute *nvmet_root_attrs[] = {

	&nvmet_root_attr_discovery_nqn,

	NULL,

};



static const struct config_item_type nvmet_root_type = {

	.ct_attrs		= nvmet_root_attrs,

	.ct_owner		= THIS_MODULE,

};

drivers/nvme/target/core.c

+7 −0
Original line number Diff line number Diff line
@@ -1541,6 +1541,13 @@ static struct nvmet_subsys *nvmet_find_get_subsys(struct nvmet_port *port, 
	}



	down_read(&nvmet_config_sem);

	if (!strncmp(nvmet_disc_subsys->subsysnqn, subsysnqn,

				NVMF_NQN_SIZE)) {

		if (kref_get_unless_zero(&nvmet_disc_subsys->ref)) {

			up_read(&nvmet_config_sem);

			return nvmet_disc_subsys;

		}

	}

	list_for_each_entry(p, &port->subsystems, entry) {

		if (!strncmp(p->subsys->subsysnqn, subsysnqn,

				NVMF_NQN_SIZE)) {