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: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Max Gurtovoy 2021-02-17 17:19:40 +00:00 committed by Christoph Hellwig
parent 32feb6de47
commit d9f273b758
4 changed files with 50 additions and 45 deletions

View File

@ -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), ' ');

View File

@ -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,
const char *page, size_t count)
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)
subsys->model_number = kmemdup_nul(page, len, GFP_KERNEL);
if (!subsys->model_number)
return -ENOMEM;
return count;
}
new_model = kzalloc(sizeof(*new_model) + len + 1, GFP_KERNEL);
if (!new_model) {
kfree(new_model_number);
return -ENOMEM;
}
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);

View File

@ -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);
}

View File

@ -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;