Re: [PATCH 3/3] lightnvm: export per lun information to user

["Matias Bjørling" <mb@lightnvm.io>]

On 03/19/2016 05:58 PM, Wenwei Tao wrote:
> Export per lun information to user, let the user
> know more detail information about underlying device.
>
> Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
> ---
>   drivers/lightnvm/core.c       | 59 ++++++++++++++++++++++++++++++++++++++++++-
>   drivers/lightnvm/gennvm.c     | 34 +++++++++++++++++++++++++
>   include/linux/lightnvm.h      |  3 +++
>   include/uapi/linux/lightnvm.h | 23 +++++++++++++++++
>   4 files changed, 118 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 84bc72d..7701eab 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -28,7 +28,6 @@
>   #include <linux/miscdevice.h>
>   #include <linux/lightnvm.h>
>   #include <linux/sched/sysctl.h>
> -#include <uapi/linux/lightnvm.h>
>
>   static LIST_HEAD(nvm_targets);
>   static LIST_HEAD(nvm_mgrs);
> @@ -1041,6 +1040,62 @@ static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
>   	return __nvm_configure_remove(&remove);
>   }
>
> +static long nvm_ioctl_dev_luns_status(struct file *file, void __user *arg)
> +{
> +	struct nvm_dev *dev;
> +	struct nvm_ioctl_luns_status *status;
> +	long ret = -EINVAL;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +
> +	status = kzalloc(sizeof(struct nvm_ioctl_luns_status), GFP_KERNEL);
> +	if (!status)
> +		return -ENOMEM;
> +
> +	if (copy_from_user(status, arg,
> +		sizeof(struct nvm_ioctl_luns_status))) {
> +		ret = -EFAULT;
> +		goto out;
> +	}
> +
> +	status->dev[DISK_NAME_LEN - 1] = '\0';
> +	down_write(&nvm_lock);
> +	dev = nvm_find_nvm_dev(status->dev);
> +	up_write(&nvm_lock);
> +	if (!dev) {
> +		pr_err("nvm: device not found\n");
> +		goto out;
> +	}
> +
> +	if (!dev->mt) {
> +		pr_info("nvm: device has no media manager registered.\n");
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	if (status->lun_begin > status->lun_end ||
> +			status->lun_end > dev->nr_luns) {
> +		pr_err("nvm: lun out of bound (%u:%u > %u)\n",
> +			status->lun_begin, status->lun_end, dev->nr_luns);
> +		goto out;
> +	}
> +
> +	dev->mt->get_luns_status(dev, status);
> +
> +	if (copy_to_user(arg, status,
> +			 sizeof(struct nvm_ioctl_luns_status))) {
> +		ret = -EFAULT;
> +		goto out;
> +	}
> +
> +	ret = 0;
> +
> +out:
> +	kfree(status);
> +	return ret;
> +}
> +
>   static void nvm_setup_nvm_sb_info(struct nvm_sb_info *info)
>   {
>   	info->seqnr = 1;
> @@ -1150,6 +1205,8 @@ static long nvm_ctl_ioctl(struct file *file, uint cmd, unsigned long arg)
>   		return nvm_ioctl_dev_create(file, argp);
>   	case NVM_DEV_REMOVE:
>   		return nvm_ioctl_dev_remove(file, argp);
> +	case NVM_DEV_LUNS_STATUS:
> +		return nvm_ioctl_dev_luns_status(file, argp);
>   	case NVM_DEV_INIT:
>   		return nvm_ioctl_dev_init(file, argp);
>   	case NVM_DEV_FACTORY:
> diff --git a/drivers/lightnvm/gennvm.c b/drivers/lightnvm/gennvm.c
> index 72e124a..b2390f4 100644
> --- a/drivers/lightnvm/gennvm.c
> +++ b/drivers/lightnvm/gennvm.c
> @@ -502,6 +502,39 @@ static struct nvm_lun *gennvm_get_lun(struct nvm_dev *dev, int lunid)
>   	return &gn->luns[lunid].vlun;
>   }
>
> +static void gennvm_get_luns_status(struct nvm_dev *dev,
> +		struct nvm_ioctl_luns_status *status)
> +{
> +	int i, lun_begin = status->lun_begin;
> +	int nr_luns, lun_end = status->lun_end;
> +	struct gen_nvm *gn = dev->mp;
> +	struct nvm_lun_status *lun_stat;
> +	struct gen_lun *lun;
> +
> +	status->nr_luns = dev->nr_luns;
> +	nr_luns = min(lun_end - lun_begin + 1,
> +				NVM_LUNS_STATUS);
> +
> +	for (i = 0;  i < nr_luns; i++) {
> +		lun = &gn->luns[i + lun_begin];
> +		lun_stat = &status->status[i];
> +
> +		lun_stat->reserved =
> +			test_bit(i + lun_begin, dev->lun_map);
> +		lun_stat->id = lun->vlun.id;
> +		lun_stat->lun_id = lun->vlun.lun_id;
> +		lun_stat->chnl_id = lun->vlun.chnl_id;
> +		lun_stat->nr_free_blocks =
> +			lun->vlun.nr_free_blocks;
> +		lun_stat->nr_open_blocks =
> +			lun->vlun.nr_open_blocks;
> +		lun_stat->nr_closed_blocks =
> +			lun->vlun.nr_closed_blocks;
> +		lun_stat->nr_bad_blocks =
> +			lun->vlun.nr_bad_blocks;
> +	}
> +}
> +
>   static void gennvm_lun_info_print(struct nvm_dev *dev)
>   {
>   	struct gen_nvm *gn = dev->mp;
> @@ -542,6 +575,7 @@ static struct nvmm_type gennvm = {
>   	.get_lun		= gennvm_get_lun,
>   	.reserve_lun		= gennvm_reserve_lun,
>   	.release_lun		= gennvm_release_lun,
> +	.get_luns_status	= gennvm_get_luns_status,
>   	.lun_info_print		= gennvm_lun_info_print,
>
>   	.get_area		= gennvm_get_area,
> diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
> index b941a8c..88b95f9 100644
> --- a/include/linux/lightnvm.h
> +++ b/include/linux/lightnvm.h
> @@ -472,6 +472,8 @@ typedef int (nvmm_erase_blk_fn)(struct nvm_dev *, struct nvm_block *,
>   typedef struct nvm_lun *(nvmm_get_lun_fn)(struct nvm_dev *, int);
>   typedef int (nvmm_reserve_lun)(struct nvm_dev *, int);
>   typedef void (nvmm_release_lun)(struct nvm_dev *, int);
> +typedef void (nvmm_get_luns_status)(struct nvm_dev *,
> +				struct nvm_ioctl_luns_status *);
>   typedef void (nvmm_lun_info_print_fn)(struct nvm_dev *);
>
>   typedef int (nvmm_get_area_fn)(struct nvm_dev *, sector_t *, sector_t);
> @@ -502,6 +504,7 @@ struct nvmm_type {
>   	nvmm_release_lun *release_lun;
>
>   	/* Statistics */
> +	nvmm_get_luns_status *get_luns_status;
>   	nvmm_lun_info_print_fn *lun_info_print;
>
>   	nvmm_get_area_fn *get_area;
> diff --git a/include/uapi/linux/lightnvm.h b/include/uapi/linux/lightnvm.h
> index 6dbf6a0..2d52d6d 100644
> --- a/include/uapi/linux/lightnvm.h
> +++ b/include/uapi/linux/lightnvm.h
> @@ -36,6 +36,7 @@
>   #define NVM_MMTYPE_LEN 8
>
>   #define NVM_LUNS_MAX 768
> +#define NVM_LUNS_STATUS 64
>
>   #define NVM_CTRL_FILE "/dev/lightnvm/control"
>
> @@ -110,6 +111,25 @@ struct nvm_ioctl_remove {
>   	__u32 flags;
>   };
>
> +struct nvm_lun_status {
> +	bool reserved;
> +	__u32 id;
> +	__u32 lun_id;
> +	__u32 chnl_id;
> +	__u32 nr_open_blocks;
> +	__u32 nr_closed_blocks;
> +	__u32 nr_free_blocks;
> +	__u32 nr_bad_blocks;
> +};
> +
> +struct nvm_ioctl_luns_status {
> +	char dev[DISK_NAME_LEN];
> +	__u32 nr_luns;
> +	__u32 lun_begin;
> +	__u32 lun_end;
> +	struct nvm_lun_status status[NVM_LUNS_STATUS];
> +};
> +
>   struct nvm_ioctl_dev_init {
>   	char dev[DISK_NAME_LEN];		/* open-channel SSD device */
>   	char mmtype[NVM_MMTYPE_LEN];		/* register to media manager */
> @@ -140,6 +160,7 @@ enum {
>   	/* device level cmds */
>   	NVM_DEV_CREATE_CMD,
>   	NVM_DEV_REMOVE_CMD,
> +	NVM_DEV_LUNS_STATUS_CMD,
>
>   	/* Init a device to support LightNVM media managers */
>   	NVM_DEV_INIT_CMD,
> @@ -158,6 +179,8 @@ enum {
>   						struct nvm_ioctl_create)
>   #define NVM_DEV_REMOVE		_IOW(NVM_IOCTL, NVM_DEV_REMOVE_CMD, \
>   						struct nvm_ioctl_remove)
> +#define NVM_DEV_LUNS_STATUS	_IOW(NVM_IOCTL, NVM_DEV_LUNS_STATUS_CMD, \
> +						struct nvm_ioctl_luns_status)
>   #define NVM_DEV_INIT		_IOW(NVM_IOCTL, NVM_DEV_INIT_CMD, \
>   						struct nvm_ioctl_dev_init)
>   #define NVM_DEV_FACTORY		_IOW(NVM_IOCTL, NVM_DEV_FACTORY_CMD, \
>

I think it will be better to expose this through sysfs. There is a patch 
coming up that will add support and enable us to get the luns.