Commit d9f273b7 authored by Max Gurtovoy's avatar Max Gurtovoy Committed by Christoph Hellwig
Browse files

nvmet: model_number must be immutable once set 



In case we have already established connection to nvmf target, it
shouldn't be allowed to change the model_number. E.g. if someone will
identify ctrl and get model_number of "my_model" later on will change
the model_numbel via configfs to "my_new_model" this will break the NVMe
specification for "Get Log Page – Persistent Event Log" that refers to
Model Number as: "This field contains the same value as reported in the
Model Number field of the Identify Controller data structure, bytes
63:24."

Although it doesn't mentioned explicitly that this field can't be
changed, we can assume it.

So allow setting this field only once: using configfs or in the first
identify ctrl operation.

Signed-off-by: default avatarMax Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 32feb6de

drivers/nvme/target/admin-cmd.c

+25 −11
Original line number Diff line number Diff line
@@ -313,27 +313,40 @@ static void nvmet_execute_get_log_page(struct nvmet_req *req) 
	nvmet_req_complete(req, NVME_SC_INVALID_FIELD | NVME_SC_DNR);

}



static void nvmet_id_set_model_number(struct nvme_id_ctrl *id,

				      struct nvmet_subsys *subsys)

static u16 nvmet_set_model_number(struct nvmet_subsys *subsys)

{

	const char *model = NVMET_DEFAULT_CTRL_MODEL;

	struct nvmet_subsys_model *subsys_model;

	u16 status = 0;



	rcu_read_lock();

	subsys_model = rcu_dereference(subsys->model);

	if (subsys_model)

		model = subsys_model->number;

	memcpy_and_pad(id->mn, sizeof(id->mn), model, strlen(model), ' ');

	rcu_read_unlock();

	mutex_lock(&subsys->lock);

	if (!subsys->model_number) {

		subsys->model_number =

			kstrdup(NVMET_DEFAULT_CTRL_MODEL, GFP_KERNEL);

		if (!subsys->model_number)

			status = NVME_SC_INTERNAL;

	}

	mutex_unlock(&subsys->lock);



	return status;

}



static void nvmet_execute_identify_ctrl(struct nvmet_req *req)

{

	struct nvmet_ctrl *ctrl = req->sq->ctrl;

	struct nvmet_subsys *subsys = ctrl->subsys;

	struct nvme_id_ctrl *id;

	u32 cmd_capsule_size;

	u16 status = 0;



	/*

	 * If there is no model number yet, set it now.  It will then remain

	 * stable for the life time of the subsystem.

	 */

	if (!subsys->model_number) {

		status = nvmet_set_model_number(subsys);

		if (status)

			goto out;

	}



	id = kzalloc(sizeof(*id), GFP_KERNEL);

	if (!id) {

		status = NVME_SC_INTERNAL;
@@ -347,7 +360,8 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req) 
	memset(id->sn, ' ', sizeof(id->sn));

	bin2hex(id->sn, &ctrl->subsys->serial,

		min(sizeof(ctrl->subsys->serial), sizeof(id->sn) / 2));

	nvmet_id_set_model_number(id, ctrl->subsys);

	memcpy_and_pad(id->mn, sizeof(id->mn), subsys->model_number,

		       strlen(subsys->model_number), ' ');

	memcpy_and_pad(id->fr, sizeof(id->fr),

		       UTS_RELEASE, strlen(UTS_RELEASE), ' ');

drivers/nvme/target/configfs.c

+23 −27
Original line number Diff line number Diff line
@@ -1118,16 +1118,12 @@ static ssize_t nvmet_subsys_attr_model_show(struct config_item *item, 
					    char *page)

{

	struct nvmet_subsys *subsys = to_subsys(item);

	struct nvmet_subsys_model *subsys_model;

	char *model = NVMET_DEFAULT_CTRL_MODEL;

	int ret;



	rcu_read_lock();

	subsys_model = rcu_dereference(subsys->model);

	if (subsys_model)

		model = subsys_model->number;

	ret = snprintf(page, PAGE_SIZE, "%s\n", model);

	rcu_read_unlock();

	mutex_lock(&subsys->lock);

	ret = snprintf(page, PAGE_SIZE, "%s\n", subsys->model_number ?

			subsys->model_number : NVMET_DEFAULT_CTRL_MODEL);

	mutex_unlock(&subsys->lock);



	return ret;

}
@@ -1138,14 +1134,17 @@ static bool nvmet_is_ascii(const char c) 
	return c >= 0x20 && c <= 0x7e;

}



static ssize_t nvmet_subsys_attr_model_store(struct config_item *item,

static ssize_t nvmet_subsys_attr_model_store_locked(struct nvmet_subsys *subsys,

		const char *page, size_t count)

{

	struct nvmet_subsys *subsys = to_subsys(item);

	struct nvmet_subsys_model *new_model;

	char *new_model_number;

	int pos = 0, len;



	if (subsys->model_number) {

		pr_err("Can't set model number. %s is already assigned\n",

		       subsys->model_number);

		return -EINVAL;

	}



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

	if (!len)

		return -EINVAL;
@@ -1155,28 +1154,25 @@ static ssize_t nvmet_subsys_attr_model_store(struct config_item *item, 
			return -EINVAL;

	}



	new_model_number = kmemdup_nul(page, len, GFP_KERNEL);

	if (!new_model_number)

		return -ENOMEM;



	new_model = kzalloc(sizeof(*new_model) + len + 1, GFP_KERNEL);

	if (!new_model) {

		kfree(new_model_number);

	subsys->model_number = kmemdup_nul(page, len, GFP_KERNEL);

	if (!subsys->model_number)

		return -ENOMEM;

	return count;

}

	memcpy(new_model->number, new_model_number, len);



static ssize_t nvmet_subsys_attr_model_store(struct config_item *item,

					     const char *page, size_t count)

{

	struct nvmet_subsys *subsys = to_subsys(item);

	ssize_t ret;



	down_write(&nvmet_config_sem);

	mutex_lock(&subsys->lock);

	new_model = rcu_replace_pointer(subsys->model, new_model,

					mutex_is_locked(&subsys->lock));

	ret = nvmet_subsys_attr_model_store_locked(subsys, page, count);

	mutex_unlock(&subsys->lock);

	up_write(&nvmet_config_sem);



	kfree_rcu(new_model, rcuhead);

	kfree(new_model_number);



	return count;

	return ret;

}

CONFIGFS_ATTR(nvmet_subsys_, attr_model);

drivers/nvme/target/core.c

+1 −1
Original line number Diff line number Diff line
@@ -1532,7 +1532,7 @@ static void nvmet_subsys_free(struct kref *ref) 
	nvmet_passthru_subsys_free(subsys);



	kfree(subsys->subsysnqn);

	kfree_rcu(subsys->model, rcuhead);

	kfree(subsys->model_number);

	kfree(subsys);

}

drivers/nvme/target/nvmet.h

+1 −6
Original line number Diff line number Diff line
@@ -208,11 +208,6 @@ struct nvmet_ctrl { 
	bool			pi_support;

};



struct nvmet_subsys_model {

	struct rcu_head		rcuhead;

	char			number[];

};



struct nvmet_subsys {

	enum nvme_subsys_type	type;
@@ -242,7 +237,7 @@ struct nvmet_subsys { 
	struct config_group	namespaces_group;

	struct config_group	allowed_hosts_group;



	struct nvmet_subsys_model	__rcu *model;

	char			*model_number;



#ifdef CONFIG_NVME_TARGET_PASSTHRU

	struct nvme_ctrl	*passthru_ctrl;