[PATCH 4/4] nvmet: make ver stable once connection established

[Chaitanya Kulkarni]

On 4/20/21 02:09, Max Gurtovoy wrote:
> From: Noam Gottlieb <ngottlieb at nvidia.com>
>
> Once some host has connected to the nvmf target, make sure that the
> version number is stable and cannot be changed.
>
> Reviewed-by: Max Gurtovoy <mgurtovoy at nvidia.com>
> Signed-off-by: Noam Gottlieb <ngottlieb at nvidia.com>
> ---
>  drivers/nvme/target/configfs.c | 36 +++++++++++++++++++++++++++++-----
>  1 file changed, 31 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
> index 61a9a52da30d..2c7aebd4d529 100644
> --- a/drivers/nvme/target/configfs.c
> +++ b/drivers/nvme/target/configfs.c
> @@ -1007,13 +1007,26 @@ static ssize_t nvmet_subsys_attr_version_show(struct config_item *item,
>  			NVME_MINOR(subsys->ver));
>  }
>  
> -static ssize_t nvmet_subsys_attr_version_store(struct config_item *item,
> -					       const char *page, size_t count)
> +static ssize_t
> +nvmet_subsys_attr_version_store_locked(struct nvmet_subsys *subsys,
> +		const char *page, size_t count)
>  {

Seems like we lost the indentation in above line which was there previously.

> -	struct nvmet_subsys *subsys = to_subsys(item);
>  	int major, minor, tertiary = 0;
>  	int ret;
>  
> +	if (subsys->subsys_discovered) {
> +		if (NVME_TERTIARY(subsys->ver))
> +			pr_err("Can't set version number. %llu.%llu.%llu is already assigned\n",
> +			       NVME_MAJOR(subsys->ver),
> +			       NVME_MINOR(subsys->ver),
> +			       NVME_TERTIARY(subsys->ver));
> +		else
> +			pr_err("Can't set version number. %llu.%llu is already assigned\n",
> +			       NVME_MAJOR(subsys->ver),
> +			       NVME_MINOR(subsys->ver));
> +		return -EINVAL;
> +	}
> +

Can you create a helper to for about error reporting so we can avoid
extra long lines whenever itis possible something like :-

        if (subsys->subsys_discovered)
            return nvmet_subsys_discover_err(subsys);

>  	/* passthru subsystems use the underlying controller's version */
>  	if (nvmet_passthru_ctrl(subsys))
>  		return -EINVAL;
> @@ -1022,12 +1035,25 @@ static ssize_t nvmet_subsys_attr_version_store(struct config_item *item,
>  	if (ret != 2 && ret != 3)
>  		return -EINVAL;
>  
> -	down_write(&nvmet_config_sem);
>  	subsys->ver = NVME_VS(major, minor, tertiary);
> -	up_write(&nvmet_config_sem);
>  
>  	return count;
>  }
> +
> +static ssize_t nvmet_subsys_attr_version_store(struct config_item *item,
> +					       const char *page, size_t count)
> +{
> +	struct nvmet_subsys *subsys = to_subsys(item);
> +	int ret;
> +

nit:- ret variable type should be ssize_t
nvmet_subsys_attr_version_store_locke().

> +	down_write(&nvmet_config_sem);
> +	mutex_lock(&subsys->lock);
> +	ret = nvmet_subsys_attr_version_store_locked(subsys, page, count);
> +	mutex_unlock(&subsys->lock);
> +	up_write(&nvmet_config_sem);
> +
> +	return ret;
> +}
>  CONFIGFS_ATTR(nvmet_subsys_, attr_version);
>  
>  /* See Section 1.5 of NVMe 1.4 */