Re: [PATCH 12/13] lightnvm: pblk: close opened chunks

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> On 4 Mar 2019, at 14.18, Matias Bjørling <mb@xxxxxxxxxxx> wrote:
> 
> On 3/4/19 9:27 AM, Javier González wrote:
>>> On 27 Feb 2019, at 18.14, Igor Konopko <igor.j.konopko@xxxxxxxxx> wrote:
>>> 
>>> When we creating pblk instance with factory
>>> flag, there is a possibility that some chunks
>>> are in open state, which does not allow to
>>> issue erase request to them directly. Such a
>>> chunk should be filled with some empty data in
>>> order to achieve close state. Without that we
>>> are risking that some erase operation will be
>>> rejected by the drive due to inproper chunk
>>> state.
>>> 
>>> This patch implements closing chunk logic in pblk
>>> for that case, when creating instance with factory
>>> flag in order to fix that issue
>>> 
>>> Signed-off-by: Igor Konopko <igor.j.konopko@xxxxxxxxx>
>>> ---
>>> drivers/lightnvm/pblk-core.c | 114 +++++++++++++++++++++++++++++++++++
>>> drivers/lightnvm/pblk-init.c |  14 ++++-
>>> drivers/lightnvm/pblk.h      |   2 +
>>> 3 files changed, 128 insertions(+), 2 deletions(-)
>>> 
>>> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
>>> index fa4dc05608ff..d3c45393f093 100644
>>> --- a/drivers/lightnvm/pblk-core.c
>>> +++ b/drivers/lightnvm/pblk-core.c
>>> @@ -161,6 +161,120 @@ struct nvm_chk_meta *pblk_chunk_get_off(struct pblk *pblk,
>>> 	return meta + ch_off + lun_off + chk_off;
>>> }
>>> 
>>> +static void pblk_close_chunk(struct pblk *pblk, struct ppa_addr ppa, int count)
>>> +{
>>> +	struct nvm_tgt_dev *dev = pblk->dev;
>>> +	struct nvm_geo *geo = &dev->geo;
>>> +	struct bio *bio;
>>> +	struct ppa_addr *ppa_list;
>>> +	struct nvm_rq rqd;
>>> +	void *meta_list, *data;
>>> +	dma_addr_t dma_meta_list, dma_ppa_list;
>>> +	int i, rq_ppas, rq_len, ret;
>>> +
>>> +	meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL, &dma_meta_list);
>>> +	if (!meta_list)
>>> +		return;
>>> +
>>> +	ppa_list = meta_list + pblk_dma_meta_size(pblk);
>>> +	dma_ppa_list = dma_meta_list + pblk_dma_meta_size(pblk);
>>> +
>>> +	rq_ppas = pblk_calc_secs(pblk, count, 0, false);
>>> +	if (!rq_ppas)
>>> +		rq_ppas = pblk->min_write_pgs;
>>> +	rq_len = rq_ppas * geo->csecs;
>>> +
>>> +	data = kzalloc(rq_len, GFP_KERNEL);
>>> +	if (!data)
>>> +		goto free_meta_list;
>>> +
>>> +	memset(&rqd, 0, sizeof(struct nvm_rq));
>>> +	rqd.opcode = NVM_OP_PWRITE;
>>> +	rqd.nr_ppas = rq_ppas;
>>> +	rqd.meta_list = meta_list;
>>> +	rqd.ppa_list = ppa_list;
>>> +	rqd.dma_ppa_list = dma_ppa_list;
>>> +	rqd.dma_meta_list = dma_meta_list;
>>> +
>>> +next_rq:
>>> +	bio = bio_map_kern(dev->q, data, rq_len, GFP_KERNEL);
>>> +	if (IS_ERR(bio))
>>> +		goto out_next;
>>> +
>>> +	bio->bi_iter.bi_sector = 0; /* artificial bio */
>>> +	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
>>> +
>>> +	rqd.bio = bio;
>>> +	for (i = 0; i < rqd.nr_ppas; i++) {
>>> +		rqd.ppa_list[i] = ppa;
>>> +		rqd.ppa_list[i].m.sec += i;
>>> +		pblk_get_meta(pblk, meta_list, i)->lba =
>>> +					cpu_to_le64(ADDR_EMPTY);
>>> +	}
>>> +
>>> +	ret = nvm_submit_io_sync(dev, &rqd);
>>> +	if (ret) {
>>> +		bio_put(bio);
>>> +		goto out_next;
>>> +	}
>>> +
>>> +	if (rqd.error)
>>> +		goto free_data;
>>> +
>>> +out_next:
>>> +	count -= rqd.nr_ppas;
>>> +	ppa.m.sec += rqd.nr_ppas;
>>> +	if (count > 0)
>>> +		goto next_rq;
>>> +
>>> +free_data:
>>> +	kfree(data);
>>> +free_meta_list:
>>> +	nvm_dev_dma_free(dev->parent, meta_list, dma_meta_list);
>>> +}
>>> +
>>> +void pblk_close_opened_chunks(struct pblk *pblk, struct nvm_chk_meta *meta)
>>> +{
>>> +	struct nvm_tgt_dev *dev = pblk->dev;
>>> +	struct nvm_geo *geo = &dev->geo;
>>> +	struct nvm_chk_meta *chunk_meta;
>>> +	struct ppa_addr ppa;
>>> +	int i, j, k, count;
>>> +
>>> +	for (i = 0; i < geo->num_chk; i++) {
>>> +		for (j = 0; j < geo->num_lun; j++) {
>>> +			for (k = 0; k < geo->num_ch; k++) {
>>> +				ppa.ppa = 0;
>>> +				ppa.m.grp = k;
>>> +				ppa.m.pu = j;
>>> +				ppa.m.chk = i;
>>> +
>>> +				chunk_meta = pblk_chunk_get_off(pblk,
>>> +								meta, ppa);
>>> +				if (chunk_meta->state == NVM_CHK_ST_OPEN) {
>>> +					ppa.m.sec = chunk_meta->wp;
>>> +					count = geo->clba - chunk_meta->wp;
>>> +					pblk_close_chunk(pblk, ppa, count);
>>> +				}
>>> +			}
>>> +		}
>>> +	}
>>> +}
>>> +
>>> +bool pblk_are_opened_chunks(struct pblk *pblk, struct nvm_chk_meta *meta)
>>> +{
>>> +	struct nvm_tgt_dev *dev = pblk->dev;
>>> +	struct nvm_geo *geo = &dev->geo;
>>> +	int i;
>>> +
>>> +	for (i = 0; i < geo->all_luns; i++) {
>>> +		if (meta[i].state == NVM_CHK_ST_OPEN)
>>> +			return true;
>>> +	}
>>> +
>>> +	return false;
>>> +}
>>> +
>>> void __pblk_map_invalidate(struct pblk *pblk, struct pblk_line *line,
>>> 			   u64 paddr)
>>> {
>>> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
>>> index 9913a4514eb6..83abe6960b46 100644
>>> --- a/drivers/lightnvm/pblk-init.c
>>> +++ b/drivers/lightnvm/pblk-init.c
>>> @@ -1028,13 +1028,14 @@ static int pblk_line_meta_init(struct pblk *pblk)
>>> 	return 0;
>>> }
>>> 
>>> -static int pblk_lines_init(struct pblk *pblk)
>>> +static int pblk_lines_init(struct pblk *pblk, bool factory_init)
>>> {
>>> 	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
>>> 	struct pblk_line *line;
>>> 	void *chunk_meta;
>>> 	int nr_free_chks = 0;
>>> 	int i, ret;
>>> +	bool retry = false;
>>> 
>>> 	ret = pblk_line_meta_init(pblk);
>>> 	if (ret)
>>> @@ -1048,12 +1049,21 @@ static int pblk_lines_init(struct pblk *pblk)
>>> 	if (ret)
>>> 		goto fail_free_meta;
>>> 
>>> +get_chunk_meta:
>>> 	chunk_meta = pblk_get_chunk_meta(pblk);
>>> 	if (IS_ERR(chunk_meta)) {
>>> 		ret = PTR_ERR(chunk_meta);
>>> 		goto fail_free_luns;
>>> 	}
>>> 
>>> +	if (factory_init && !retry &&
>>> +	    pblk_are_opened_chunks(pblk, chunk_meta)) {
>>> +		pblk_close_opened_chunks(pblk, chunk_meta);
>>> +		retry = true;
>>> +		vfree(chunk_meta);
>>> +		goto get_chunk_meta;
>>> +	}
>>> +
>>> 	pblk->lines = kcalloc(l_mg->nr_lines, sizeof(struct pblk_line),
>>> 								GFP_KERNEL);
>>> 	if (!pblk->lines) {
>>> @@ -1244,7 +1254,7 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
>>> 		goto fail;
>>> 	}
>>> 
>>> -	ret = pblk_lines_init(pblk);
>>> +	ret = pblk_lines_init(pblk, flags & NVM_TARGET_FACTORY);
>>> 	if (ret) {
>>> 		pblk_err(pblk, "could not initialize lines\n");
>>> 		goto fail_free_core;
>>> diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
>>> index b266563508e6..b248642c4dfb 100644
>>> --- a/drivers/lightnvm/pblk.h
>>> +++ b/drivers/lightnvm/pblk.h
>>> @@ -793,6 +793,8 @@ struct nvm_chk_meta *pblk_get_chunk_meta(struct pblk *pblk);
>>> struct nvm_chk_meta *pblk_chunk_get_off(struct pblk *pblk,
>>> 					      struct nvm_chk_meta *lp,
>>> 					      struct ppa_addr ppa);
>>> +void pblk_close_opened_chunks(struct pblk *pblk, struct nvm_chk_meta *_meta);
>>> +bool pblk_are_opened_chunks(struct pblk *pblk, struct nvm_chk_meta *_meta);
>>> void pblk_log_write_err(struct pblk *pblk, struct nvm_rq *rqd);
>>> void pblk_log_read_err(struct pblk *pblk, struct nvm_rq *rqd);
>>> int pblk_submit_io(struct pblk *pblk, struct nvm_rq *rqd);
>>> --
>>> 2.17.1
>> I know that the OCSSD 2.0 spec does not allow to transition from open to
>> free, but to me this is a spec bug as there is no underlying issue in
>> reading an open block. Note that all controllers I know support this,
>> and the upcoming Denali spec. fixes this too.
> 
> The issue is not whether the chunk can be read. It is that going from
> Open -> Empty -> Open causes an erase on some implementations, and
> causes the media to wear out prematurely.

If the host is padding data to be able to close, the effect on wear is the same.

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