Re: [PATCH 09/15] lightnvm: implement get log report chunk helpers

[Javier Gonzalez]

> On 1 Mar 2018, at 11.40, Matias BjÃrling <mb@xxxxxxxxxxx> wrote:
> 
> On 02/28/2018 04:49 PM, Javier GonzÃlez 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 GonzÃlez <javier@xxxxxxxxxxxx>
>> ---
>>  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.

Javier

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