> On 1 Mar 2018, at 12.51, Matias Bjørling <m...@lightnvm.io> wrote:
> 
> On 03/01/2018 12:02 PM, Javier Gonzalez wrote:
>>> On 1 Mar 2018, at 11.40, Matias Bjørling <m...@lightnvm.io> wrote:
>>> 
>>> On 02/28/2018 04:49 PM, Javier González wrote:
>>>> The 2.0 spec provides a report chunk log page that can be retrieved
>>>> using the stangard nvme get log page. This replaces the dedicated
>>>> get/put bad block table in 1.2.
>>>> This patch implements the helper functions to allow targets retrieve the
>>>> chunk metadata using get log page. It makes nvme_get_log_ext available
>>>> outside of nvme core so that we can use it form lightnvm.
>>>> Signed-off-by: Javier González <jav...@cnexlabs.com>
>>>> ---
>>>>  drivers/lightnvm/core.c      | 11 +++++++
>>>>  drivers/nvme/host/core.c     |  6 ++--
>>>>  drivers/nvme/host/lightnvm.c | 74 
>>>> ++++++++++++++++++++++++++++++++++++++++++++
>>>>  drivers/nvme/host/nvme.h     |  3 ++
>>>>  include/linux/lightnvm.h     | 24 ++++++++++++++
>>>>  5 files changed, 115 insertions(+), 3 deletions(-)
>>>> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
>>>> index ed33e0b11788..4141871f460d 100644
>>>> --- a/drivers/lightnvm/core.c
>>>> +++ b/drivers/lightnvm/core.c
>>>> @@ -712,6 +712,17 @@ static void nvm_free_rqd_ppalist(struct nvm_tgt_dev 
>>>> *tgt_dev,
>>>>    nvm_dev_dma_free(tgt_dev->parent, rqd->ppa_list, rqd->dma_ppa_list);
>>>>  }
>>>>  +int nvm_get_chunk_meta(struct nvm_tgt_dev *tgt_dev, struct nvm_chk_meta 
>>>> *meta,
>>>> +          struct ppa_addr ppa, int nchks)
>>>> +{
>>>> +  struct nvm_dev *dev = tgt_dev->parent;
>>>> +
>>>> +  nvm_ppa_tgt_to_dev(tgt_dev, &ppa, 1);
>>>> +
>>>> +  return dev->ops->get_chk_meta(tgt_dev->parent, meta,
>>>> +                                          (sector_t)ppa.ppa, nchks);
>>>> +}
>>>> +EXPORT_SYMBOL(nvm_get_chunk_meta);
>>>>    int nvm_set_tgt_bb_tbl(struct nvm_tgt_dev *tgt_dev, struct ppa_addr 
>>>> *ppas,
>>>>                   int nr_ppas, int type)
>>>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>>>> index 2e9e9f973a75..af642ce6ba69 100644
>>>> --- a/drivers/nvme/host/core.c
>>>> +++ b/drivers/nvme/host/core.c
>>>> @@ -2127,9 +2127,9 @@ static int nvme_init_subsystem(struct nvme_ctrl 
>>>> *ctrl, struct nvme_id_ctrl *id)
>>>>    return ret;
>>>>  }
>>>>  -static int nvme_get_log_ext(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
>>>> -                      u8 log_page, void *log,
>>>> -                      size_t size, size_t offset)
>>>> +int nvme_get_log_ext(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
>>>> +               u8 log_page, void *log,
>>>> +               size_t size, size_t offset)
>>>>  {
>>>>    struct nvme_command c = { };
>>>>    unsigned long dwlen = size / 4 - 1;
>>>> diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
>>>> index f7135659f918..a1796241040f 100644
>>>> --- a/drivers/nvme/host/lightnvm.c
>>>> +++ b/drivers/nvme/host/lightnvm.c
>>>> @@ -35,6 +35,10 @@ enum nvme_nvm_admin_opcode {
>>>>    nvme_nvm_admin_set_bb_tbl       = 0xf1,
>>>>  };
>>>>  +enum nvme_nvm_log_page {
>>>> +  NVME_NVM_LOG_REPORT_CHUNK       = 0xca,
>>>> +};
>>>> +
>>>>  struct nvme_nvm_ph_rw {
>>>>    __u8                    opcode;
>>>>    __u8                    flags;
>>>> @@ -236,6 +240,16 @@ struct nvme_nvm_id20 {
>>>>    __u8                    vs[1024];
>>>>  };
>>>>  +struct nvme_nvm_chk_meta {
>>>> +  __u8    state;
>>>> +  __u8    type;
>>>> +  __u8    wi;
>>>> +  __u8    rsvd[5];
>>>> +  __le64  slba;
>>>> +  __le64  cnlb;
>>>> +  __le64  wp;
>>>> +};
>>>> +
>>>>  /*
>>>>   * Check we didn't inadvertently grow the command struct
>>>>   */
>>>> @@ -252,6 +266,9 @@ static inline void _nvme_nvm_check_size(void)
>>>>    BUILD_BUG_ON(sizeof(struct nvme_nvm_bb_tbl) != 64);
>>>>    BUILD_BUG_ON(sizeof(struct nvme_nvm_id20_addrf) != 8);
>>>>    BUILD_BUG_ON(sizeof(struct nvme_nvm_id20) != NVME_IDENTIFY_DATA_SIZE);
>>>> +  BUILD_BUG_ON(sizeof(struct nvme_nvm_chk_meta) != 32);
>>>> +  BUILD_BUG_ON(sizeof(struct nvme_nvm_chk_meta) !=
>>>> +                                          sizeof(struct nvm_chk_meta));
>>>>  }
>>>>    static void nvme_nvm_set_addr_12(struct nvm_addr_format_12 *dst,
>>>> @@ -555,6 +572,61 @@ static int nvme_nvm_set_bb_tbl(struct nvm_dev 
>>>> *nvmdev, struct ppa_addr *ppas,
>>>>    return ret;
>>>>  }
>>>>  +/*
>>>> + * Expect the lba in device format
>>>> + */
>>>> +static int nvme_nvm_get_chk_meta(struct nvm_dev *ndev,
>>>> +                           struct nvm_chk_meta *meta,
>>>> +                           sector_t slba, int nchks)
>>>> +{
>>>> +  struct nvm_geo *geo = &ndev->geo;
>>>> +  struct nvme_ns *ns = ndev->q->queuedata;
>>>> +  struct nvme_ctrl *ctrl = ns->ctrl;
>>>> +  struct nvme_nvm_chk_meta *dev_meta = (struct nvme_nvm_chk_meta *)meta;
>>>> +  struct ppa_addr ppa;
>>>> +  size_t left = nchks * sizeof(struct nvme_nvm_chk_meta);
>>>> +  size_t log_pos, offset, len;
>>>> +  int ret, i;
>>>> +
>>>> +  /* Normalize lba address space to obtain log offset */
>>>> +  ppa.ppa = slba;
>>>> +  ppa = dev_to_generic_addr(ndev, ppa);
>>>> +
>>>> +  log_pos = ppa.m.chk;
>>>> +  log_pos += ppa.m.pu * geo->num_chk;
>>>> +  log_pos += ppa.m.grp * geo->num_lun * geo->num_chk;
>>> 
>>> Why is this done?
>> The log page does not map to the lba space. You need to convert it to
>> get one chunk at a time in the format.
>>    GRP:PU:CHK
>> I can see why taking a lba as argument is better than a ppa, since users
>> might use the lbas directly, but the conversion needs to be done
>> somewhere.
> 
> Good point. I guess this is clash between the two APIs. Chunk metadata
> being laid out sequentially, while the address space is sparse.

Exactly.

> I'm good with the conversion being in the fn.

Cool. I think it is good here too, as it hides the ppa format from the
upper layers. It requires a double conversion from pblk, but it is not
on the fast path anyway...

Javier

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