Date:	Wed, 20 Jan 2016 14:03:04 +0100
From:	Matias Bjørling <mb@...htnvm.io>
To:	Wenwei Tao <ww.tao0320@...il.com>
Cc:	linux-kernel@...r.kernel.org, linux-block@...r.kernel.org
Subject: Re: [RFC PATCH 1/2] lightnvm: specify target's logical address area

On 01/15/2016 12:44 PM, Wenwei Tao wrote:
> We can create more than one target on a lightnvm
> device by specifying its begin lun and end lun.
> 
> But only specify the physical address area is not
> enough, we need to get the corresponding non-
> intersection logical address area division from
> the backend device's logcial address space.
> Otherwise the targets on the device might use
> the same logical addresses and this will cause
> incorrect information in the device's l2p table.
> 
> Signed-off-by: Wenwei Tao <ww.tao0320@...il.com>
> ---
>  drivers/lightnvm/core.c   |  1 +
>  drivers/lightnvm/gennvm.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++
>  drivers/lightnvm/gennvm.h |  7 ++++++
>  drivers/lightnvm/rrpc.c   | 44 ++++++++++++++++++++++++++++++++----
>  drivers/lightnvm/rrpc.h   |  1 +
>  include/linux/lightnvm.h  |  8 +++++++
>  6 files changed, 114 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 8f41b24..d938636 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -238,6 +238,7 @@ static int nvm_core_init(struct nvm_dev *dev)
>  				dev->nr_chnls;
>  	dev->total_pages = dev->total_blocks * dev->pgs_per_blk;
>  	INIT_LIST_HEAD(&dev->online_targets);
> +	spin_lock_init(&dev->lock);
>  
>  	return 0;
>  }
> diff --git a/drivers/lightnvm/gennvm.c b/drivers/lightnvm/gennvm.c
> index 62c6f4d..f7c4495 100644
> --- a/drivers/lightnvm/gennvm.c
> +++ b/drivers/lightnvm/gennvm.c
> @@ -20,6 +20,59 @@
>  
>  #include "gennvm.h"
>  
> +static sector_t gennvm_get_area(struct nvm_dev *dev, sector_t size)
> +{
> +	struct gen_nvm *gn = dev->mp;
> +	struct gennvm_area *area, *prev;
> +	sector_t start = 0;

Rename to begin?

> +	int page_size = dev->sec_size * dev->sec_per_pg;
> +	sector_t max = page_size * dev->total_pages >> 9;

Can we put parentheses around this, just for clarity. Maybe also rename
the variable to max_sect/max_sectors?

> +
> +	if (size > max)
> +		return -EINVAL;
> +	area = kmalloc(sizeof(*area), GFP_KERNEL);

I prefer sizeof(struct gennvm_area)

> +	if (!area)
> +		return -ENOMEM;
> +
> +	spin_lock(&dev->lock);
> +	list_for_each_entry(prev, &gn->area_list, list) {
> +		if (start + size > prev->start) {
> +			start = prev->end;
> +			continue;
> +		}
> +		break;
> +	}
> +
> +	if (start + size > max) {

Same with parentheses here. Just for clarity.

> +		spin_unlock(&dev->lock);
> +		kfree(area);
> +		return -EINVAL;
> +	}
> +
> +	area->start = start;
> +	area->end = start + size;
> +	list_add(&area->list, &prev->list);
> +	spin_unlock(&dev->lock);
> +	return start;
> +}
> +
> +static void gennvm_put_area(struct nvm_dev *dev, sector_t start)
> +{
> +	struct gen_nvm *gn = dev->mp;
> +	struct gennvm_area *area;
> +
> +	spin_lock(&dev->lock);
> +	list_for_each_entry(area, &gn->area_list, list) {
> +		if (area->start == start) {
> +			list_del(&area->list);
> +			spin_unlock(&dev->lock);
> +			kfree(area);
> +			return;
> +		}
> +	}
> +	spin_unlock(&dev->lock);
> +}
> +
>  static void gennvm_blocks_free(struct nvm_dev *dev)
>  {
>  	struct gen_nvm *gn = dev->mp;
> @@ -228,6 +281,7 @@ static int gennvm_register(struct nvm_dev *dev)
>  
>  	gn->dev = dev;
>  	gn->nr_luns = dev->nr_luns;
> +	INIT_LIST_HEAD(&gn->area_list);
>  	dev->mp = gn;
>  
>  	ret = gennvm_luns_init(dev, gn);
> @@ -506,6 +560,9 @@ static struct nvmm_type gennvm = {
>  
>  	.get_lun	= gennvm_get_lun,
>  	.lun_info_print = gennvm_lun_info_print,
> +
> +	.get_area	= gennvm_get_area,
> +	.put_area	= gennvm_put_area,
>  };
>  
>  static int __init gennvm_module_init(void)
> diff --git a/drivers/lightnvm/gennvm.h b/drivers/lightnvm/gennvm.h
> index 9c24b5b..b51813a 100644
> --- a/drivers/lightnvm/gennvm.h
> +++ b/drivers/lightnvm/gennvm.h
> @@ -39,6 +39,13 @@ struct gen_nvm {
>  
>  	int nr_luns;
>  	struct gen_lun *luns;
> +	struct list_head area_list;
> +};
> +
> +struct gennvm_area {
> +	struct list_head list;
> +	sector_t start;

Begin/end fits better.

> +	sector_t end;	/* end is excluded */
>  };
>  
>  #define gennvm_for_each_lun(bm, lun, i) \
> diff --git a/drivers/lightnvm/rrpc.c b/drivers/lightnvm/rrpc.c
> index 8628a5d..ab1d17a 100644
> --- a/drivers/lightnvm/rrpc.c
> +++ b/drivers/lightnvm/rrpc.c
> @@ -1017,7 +1017,17 @@ static int rrpc_map_init(struct rrpc *rrpc)
>  {
>  	struct nvm_dev *dev = rrpc->dev;
>  	sector_t i;
> -	int ret;
> +	u64 slba;
> +	int ret, page_size;
> +	int page_shfit, nr_pages;
> +
> +	page_size = dev->sec_per_pg * dev->sec_size;
> +	page_shfit = ilog2(page_size);
> +	nr_pages = rrpc->nr_luns *
> +		dev->nr_planes *
> +		dev->blks_per_lun *
> +		dev->pgs_per_blk;

Can the last three be replaced with dev->sec_per_lun?

> +	slba = rrpc->soffset >> (page_shfit - 9);
>  
>  	rrpc->trans_map = vzalloc(sizeof(struct rrpc_addr) * rrpc->nr_pages);
>  	if (!rrpc->trans_map)
> @@ -1040,8 +1050,7 @@ static int rrpc_map_init(struct rrpc *rrpc)
>  		return 0;
>  
>  	/* Bring up the mapping table from device */
> -	ret = dev->ops->get_l2p_tbl(dev, 0, dev->total_pages,
> -							rrpc_l2p_update, rrpc);
> +	ret = dev->ops->get_l2p_tbl(dev, slba, nr_pages, rrpc_l2p_update, rrpc);
>  	if (ret) {
>  		pr_err("nvm: rrpc: could not read L2P table.\n");
>  		return -EINVAL;
> @@ -1050,7 +1059,6 @@ static int rrpc_map_init(struct rrpc *rrpc)
>  	return 0;
>  }
>  
> -
>  /* Minimum pages needed within a lun */
>  #define PAGE_POOL_SIZE 16
>  #define ADDR_POOL_SIZE 64
> @@ -1160,12 +1168,33 @@ err:
>  	return -ENOMEM;
>  }
>  
> +static int rrpc_area_init(struct rrpc *rrpc)
> +{
> +	struct nvm_dev *dev = rrpc->dev;
> +	struct nvmm_type *mt = dev->mt;
> +	sector_t size = rrpc->nr_luns *
> +		dev->sec_per_lun *
> +		dev->sec_size;
> +
> +	size >>= 9;
> +	return mt->get_area(dev, size);
> +}
> +
> +static void rrpc_area_free(struct rrpc *rrpc)
> +{
> +	struct nvm_dev *dev = rrpc->dev;
> +	struct nvmm_type *mt = dev->mt;
> +
> +	mt->put_area(dev, rrpc->soffset);
> +}
> +
>  static void rrpc_free(struct rrpc *rrpc)
>  {
>  	rrpc_gc_free(rrpc);
>  	rrpc_map_free(rrpc);
>  	rrpc_core_free(rrpc);
>  	rrpc_luns_free(rrpc);
> +	rrpc_area_free(rrpc);
>  
>  	kfree(rrpc);
>  }
> @@ -1311,6 +1340,13 @@ static void *rrpc_init(struct nvm_dev *dev, struct gendisk *tdisk,
>  	/* simple round-robin strategy */
>  	atomic_set(&rrpc->next_lun, -1);
>  
> +	ret = rrpc_area_init(rrpc);

gennvm_get_area returns sector_t, while ret is int.

> +	if (ret < 0) {
> +		pr_err("nvm: rrpc: could not initialize area\n");
> +		return ERR_PTR(ret);
> +	}
> +	rrpc->soffset = ret;
> +
>  	ret = rrpc_luns_init(rrpc, lun_begin, lun_end);
>  	if (ret) {
>  		pr_err("nvm: rrpc: could not initialize luns\n");
> diff --git a/drivers/lightnvm/rrpc.h b/drivers/lightnvm/rrpc.h
> index a9696a0..f26ba5b 100644
> --- a/drivers/lightnvm/rrpc.h
> +++ b/drivers/lightnvm/rrpc.h
> @@ -86,6 +86,7 @@ struct rrpc {
>  	struct nvm_dev *dev;
>  	struct gendisk *disk;
>  
> +	sector_t soffset; /* logical sector offset */
>  	u64 poffset; /* physical page offset */
>  	int lun_offset;
>  
> diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
> index 034117b..4f3db10 100644
> --- a/include/linux/lightnvm.h
> +++ b/include/linux/lightnvm.h
> @@ -240,6 +240,8 @@ struct nvm_block {
>  struct nvm_dev {
>  	struct nvm_dev_ops *ops;
>  
> +	spinlock_t lock;
> +
>  	struct list_head devices;
>  	struct list_head online_targets;
>  
> @@ -388,6 +390,8 @@ typedef int (nvmm_erase_blk_fn)(struct nvm_dev *, struct nvm_block *,
>  								unsigned long);
>  typedef struct nvm_lun *(nvmm_get_lun_fn)(struct nvm_dev *, int);
>  typedef void (nvmm_lun_info_print_fn)(struct nvm_dev *);
> +typedef sector_t (nvmm_get_area_fn)(struct nvm_dev *, sector_t);
> +typedef void (nvmm_put_area_fn)(struct nvm_dev *, sector_t);
>  
>  struct nvmm_type {
>  	const char *name;
> @@ -412,6 +416,10 @@ struct nvmm_type {
>  
>  	/* Statistics */
>  	nvmm_lun_info_print_fn *lun_info_print;
> +
> +	nvmm_get_area_fn *get_area;
> +	nvmm_put_area_fn *put_area;
> +
>  	struct list_head list;
>  };
>  
> 

Both patches could use a rebase on top of the for-next branch.

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