Date:	Thu, 21 Jan 2016 15:05:44 +0800
From:	Wenwei Tao <ww.tao0320@...il.com>
To:	Matias Bjørling <mb@...htnvm.io>
Cc:	linux-kernel@...r.kernel.org, linux-block@...r.kernel.org
Subject: Re: [RFC PATCH 1/2] lightnvm: specify target's logical address area

2016-01-20 21:03 GMT+08:00 Matias Bjørling <mb@...htnvm.io>:
> 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?

okay with me.

>
>> +     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?
>

okay with me, I will add these changes in v2.

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

I use sizeof(*area) because of its short, sizeof(struct gennvm area)
is also okay with me.

>> +     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.
>

okay

>> +             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.
>

I will change it in v2.

>> +     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?
>

I'm not quite sure about this.
the original code use dev->total_pages as the nlb, seems like the
granularity is page not sector.

>> +     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.
>
I will rebase v2 on top of the for-next branch.

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