Re: [PATCH v13 2/5] gennvm: Generic NVM manager

[Dongsheng Yang <yangds.fnst@cn.fujitsu.com>]

On 10/28/2015 08:30 AM, Matias Bjørling wrote:
> The implementation for Open-Channel SSDs is divided into media
[...]
> +		lun->reserved_blocks = 2; /* for GC only */
> +		lun->vlun.id = i;
> +		lun->vlun.lun_id = i % dev->luns_per_chnl;
> +		lun->vlun.chnl_id = i / dev->luns_per_chnl;

Please use do_div(). % would be not supported in some platforms, as
the kbuild pointed in V12.

Yang

> +		lun->vlun.nr_free_blocks = dev->blks_per_lun;
> +	}
> +	return 0;
> +}
> +
> +static int gennvm_block_bb(u32 lun_id, void *bb_bitmap, unsigned int nr_blocks,
> +								void *private)
> +{
> +	struct gen_nvm *gn = private;
> +	struct gen_lun *lun = &gn->luns[lun_id];
> +	struct nvm_block *block;
> +	int i;
> +
> +	if (unlikely(bitmap_empty(bb_bitmap, nr_blocks)))
> +		return 0;
> +
> +	i = -1;
> +	while ((i = find_next_bit(bb_bitmap, nr_blocks, i + 1)) <
> +			nr_blocks) {
> +		block = &lun->vlun.blocks[i];
> +		if (!block) {
> +			pr_err("gen_nvm: BB data is out of bounds.\n");
> +			return -EINVAL;
> +		}
> +		list_move_tail(&block->list, &lun->bb_list);
> +	}
> +
> +	return 0;
> +}
> +
> +static int gennvm_block_map(u64 slba, u32 nlb, __le64 *entries, void *private)
> +{
> +	struct nvm_dev *dev = private;
> +	struct gen_nvm *gn = dev->mp;
> +	sector_t max_pages = dev->total_pages * (dev->sec_size >> 9);
> +	u64 elba = slba + nlb;
> +	struct gen_lun *lun;
> +	struct nvm_block *blk;
> +	u64 i;
> +	int lun_id;
> +
> +	if (unlikely(elba > dev->total_pages)) {
> +		pr_err("gen_nvm: L2P data from device is out of bounds!\n");
> +		return -EINVAL;
> +	}
> +
> +	for (i = 0; i < nlb; i++) {
> +		u64 pba = le64_to_cpu(entries[i]);
> +
> +		if (unlikely(pba >= max_pages && pba != U64_MAX)) {
> +			pr_err("gen_nvm: L2P data entry is out of bounds!\n");
> +			return -EINVAL;
> +		}
> +
> +		/* Address zero is a special one. The first page on a disk is
> +		 * protected. It often holds internal device boot
> +		 * information.
> +		 */
> +		if (!pba)
> +			continue;
> +
> +		/* resolve block from physical address */
> +		lun_id = div_u64(pba, dev->sec_per_lun);
> +		lun = &gn->luns[lun_id];
> +
> +		/* Calculate block offset into lun */
> +		pba = pba - (dev->sec_per_lun * lun_id);
> +		blk = &lun->vlun.blocks[div_u64(pba, dev->sec_per_blk)];
> +
> +		if (!blk->type) {
> +			/* at this point, we don't know anything about the
> +			 * block. It's up to the FTL on top to re-etablish the
> +			 * block state
> +			 */
> +			list_move_tail(&blk->list, &lun->used_list);
> +			blk->type = 1;
> +			lun->vlun.nr_free_blocks--;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int gennvm_blocks_init(struct nvm_dev *dev, struct gen_nvm *gn)
> +{
> +	struct gen_lun *lun;
> +	struct nvm_block *block;
> +	sector_t lun_iter, blk_iter, cur_block_id = 0;
> +	int ret;
> +
> +	gennvm_for_each_lun(gn, lun, lun_iter) {
> +		lun->vlun.blocks = vzalloc(sizeof(struct nvm_block) *
> +							dev->blks_per_lun);
> +		if (!lun->vlun.blocks)
> +			return -ENOMEM;
> +
> +		for (blk_iter = 0; blk_iter < dev->blks_per_lun; blk_iter++) {
> +			block = &lun->vlun.blocks[blk_iter];
> +
> +			INIT_LIST_HEAD(&block->list);
> +
> +			block->lun = &lun->vlun;
> +			block->id = cur_block_id++;
> +
> +			/* First block is reserved for device */
> +			if (unlikely(lun_iter == 0 && blk_iter == 0))
> +				continue;
> +
> +			list_add_tail(&block->list, &lun->free_list);
> +		}
> +
> +		if (dev->ops->get_bb_tbl) {
> +			ret = dev->ops->get_bb_tbl(dev->q, lun->vlun.id,
> +					dev->blks_per_lun, gennvm_block_bb, gn);
> +			if (ret)
> +				pr_err("gen_nvm: could not read BB table\n");
> +		}
> +	}
> +
> +	if (dev->ops->get_l2p_tbl) {
> +		ret = dev->ops->get_l2p_tbl(dev->q, 0, dev->total_pages,
> +							gennvm_block_map, dev);
> +		if (ret) {
> +			pr_err("gen_nvm: could not read L2P table.\n");
> +			pr_warn("gen_nvm: default block initialization");
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int gennvm_register(struct nvm_dev *dev)
> +{
> +	struct gen_nvm *gn;
> +	int ret;
> +
> +	gn = kzalloc(sizeof(struct gen_nvm), GFP_KERNEL);
> +	if (!gn)
> +		return -ENOMEM;
> +
> +	gn->nr_luns = dev->nr_luns;
> +	dev->mp = gn;
> +
> +	ret = gennvm_luns_init(dev, gn);
> +	if (ret) {
> +		pr_err("gen_nvm: could not initialize luns\n");
> +		goto err;
> +	}
> +
> +	ret = gennvm_blocks_init(dev, gn);
> +	if (ret) {
> +		pr_err("gen_nvm: could not initialize blocks\n");
> +		goto err;
> +	}
> +
> +	return 1;
> +err:
> +	kfree(gn);
> +	return ret;
> +}
> +
> +static void gennvm_unregister(struct nvm_dev *dev)
> +{
> +	gennvm_blocks_free(dev);
> +	gennvm_luns_free(dev);
> +	kfree(dev->mp);
> +	dev->mp = NULL;
> +}
> +
> +static struct nvm_block *gennvm_get_blk(struct nvm_dev *dev,
> +				struct nvm_lun *vlun, unsigned long flags)
> +{
> +	struct gen_lun *lun = container_of(vlun, struct gen_lun, vlun);
> +	struct nvm_block *blk = NULL;
> +	int is_gc = flags & NVM_IOTYPE_GC;
> +
> +	BUG_ON(!lun);
> +
> +	spin_lock(&vlun->lock);
> +
> +	if (list_empty(&lun->free_list)) {
> +		pr_err_ratelimited("gen_nvm: lun %u have no free pages available",
> +								lun->vlun.id);
> +		spin_unlock(&vlun->lock);
> +		goto out;
> +	}
> +
> +	while (!is_gc && lun->vlun.nr_free_blocks < lun->reserved_blocks) {
> +		spin_unlock(&vlun->lock);
> +		goto out;
> +	}
> +
> +	blk = list_first_entry(&lun->free_list, struct nvm_block, list);
> +	list_move_tail(&blk->list, &lun->used_list);
> +	blk->type = 1;
> +
> +	lun->vlun.nr_free_blocks--;
> +
> +	spin_unlock(&vlun->lock);
> +out:
> +	return blk;
> +}
> +
> +static void gennvm_put_blk(struct nvm_dev *dev, struct nvm_block *blk)
> +{
> +	struct nvm_lun *vlun = blk->lun;
> +	struct gen_lun *lun = container_of(vlun, struct gen_lun, vlun);
> +
> +	spin_lock(&vlun->lock);
> +
> +	switch (blk->type) {
> +	case 1:
> +		list_move_tail(&blk->list, &lun->free_list);
> +		lun->vlun.nr_free_blocks++;
> +		blk->type = 0;
> +		break;
> +	case 2:
> +		list_move_tail(&blk->list, &lun->bb_list);
> +		break;
> +	default:
> +		BUG();
> +	}
> +
> +	spin_unlock(&vlun->lock);
> +}
> +
> +static void gennvm_addr_to_generic_mode(struct nvm_dev *dev, struct nvm_rq *rqd)
> +{
> +	int i;
> +
> +	if (rqd->nr_pages > 1)
> +		for (i = 0; i < rqd->nr_pages; i++)
> +			rqd->ppa_list[i] = addr_to_generic_mode(dev,
> +							rqd->ppa_list[i]);
> +	else
> +		rqd->ppa_addr = addr_to_generic_mode(dev, rqd->ppa_addr);
> +}
> +
> +static void gennvm_generic_to_addr_mode(struct nvm_dev *dev, struct nvm_rq *rqd)
> +{
> +	int i;
> +
> +	if (rqd->nr_pages > 1)
> +		for (i = 0; i < rqd->nr_pages; i++)
> +			rqd->ppa_list[i] = generic_to_addr_mode(dev,
> +							rqd->ppa_list[i]);
> +	else
> +		rqd->ppa_addr = generic_to_addr_mode(dev, rqd->ppa_addr);
> +}
> +
> +static int gennvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
> +{
> +	if (!dev->ops->submit_io)
> +		return 0;
> +
> +	/* Convert address space */
> +	gennvm_generic_to_addr_mode(dev, rqd);
> +
> +	rqd->dev = dev;
> +	return dev->ops->submit_io(dev->q, rqd);
> +}
> +
> +static void gennvm_blk_set_type(struct nvm_dev *dev, struct ppa_addr *ppa,
> +								int type)
> +{
> +	struct gen_nvm *gn = dev->mp;
> +	struct gen_lun *lun;
> +	struct nvm_block *blk;
> +
> +	BUG_ON(ppa->g.ch > dev->nr_chnls);
> +	BUG_ON(ppa->g.lun > dev->luns_per_chnl);
> +	BUG_ON(ppa->g.blk > dev->blks_per_lun);
> +
> +	lun = &gn->luns[ppa->g.lun * ppa->g.ch];
> +	blk = &lun->vlun.blocks[ppa->g.blk];
> +
> +	/* will be moved to bb list on put_blk from target */
> +	blk->type = type;
> +}
> +
> +/* mark block bad. It is expected the target recover from the error. */
> +static void gennvm_mark_blk_bad(struct nvm_dev *dev, struct nvm_rq *rqd)
> +{
> +	int i;
> +
> +	if (!dev->ops->set_bb)
> +		return;
> +
> +	if (dev->ops->set_bb(dev->q, rqd, 1))
> +		return;
> +
> +	gennvm_addr_to_generic_mode(dev, rqd);
> +
> +	/* look up blocks and mark them as bad */
> +	if (rqd->nr_pages > 1)
> +		for (i = 0; i < rqd->nr_pages; i++)
> +			gennvm_blk_set_type(dev, &rqd->ppa_list[i], 2);
> +	else
> +		gennvm_blk_set_type(dev, &rqd->ppa_addr, 2);
> +}
> +
> +static int gennvm_end_io(struct nvm_rq *rqd, int error)
> +{
> +	struct nvm_tgt_instance *ins = rqd->ins;
> +	int ret = 0;
> +
> +	switch (error) {
> +	case NVM_RSP_SUCCESS:
> +		break;
> +	case NVM_RSP_ERR_EMPTYPAGE:
> +		break;
> +	case NVM_RSP_ERR_FAILWRITE:
> +		gennvm_mark_blk_bad(rqd->dev, rqd);
> +	default:
> +		ret++;
> +	}
> +
> +	ret += ins->tt->end_io(rqd, error);
> +
> +	return ret;
> +}
> +
> +static int gennvm_erase_blk(struct nvm_dev *dev, struct nvm_block *blk,
> +							unsigned long flags)
> +{
> +	int plane_cnt = 0, pl_idx, ret;
> +	struct ppa_addr addr;
> +	struct nvm_rq rqd;
> +
> +	if (!dev->ops->erase_block)
> +		return 0;
> +
> +	addr = block_to_ppa(dev, blk);
> +
> +	if (dev->plane_mode == NVM_PLANE_SINGLE) {
> +		rqd.nr_pages = 1;
> +		rqd.ppa_addr = addr;
> +	} else {
> +		plane_cnt = (1 << dev->plane_mode);
> +		rqd.nr_pages = plane_cnt;
> +
> +		rqd.ppa_list = nvm_dev_dma_alloc(dev, GFP_KERNEL,
> +							&rqd.dma_ppa_list);
> +		if (!rqd.ppa_list) {
> +			pr_err("gen_nvm: failed to allocate dma memory\n");
> +			return -ENOMEM;
> +		}
> +
> +		for (pl_idx = 0; pl_idx < plane_cnt; pl_idx++) {
> +			addr.g.pl = pl_idx;
> +			rqd.ppa_list[pl_idx] = addr;
> +		}
> +	}
> +
> +	gennvm_generic_to_addr_mode(dev, &rqd);
> +
> +	ret = dev->ops->erase_block(dev->q, &rqd);
> +
> +	if (plane_cnt)
> +		nvm_dev_dma_free(dev, rqd.ppa_list, rqd.dma_ppa_list);
> +
> +	return ret;
> +}
> +
> +static struct nvm_lun *gennvm_get_lun(struct nvm_dev *dev, int lunid)
> +{
> +	struct gen_nvm *gn = dev->mp;
> +
> +	return &gn->luns[lunid].vlun;
> +}
> +
> +static void gennvm_free_blocks_print(struct nvm_dev *dev)
> +{
> +	struct gen_nvm *gn = dev->mp;
> +	struct gen_lun *lun;
> +	unsigned int i;
> +
> +	gennvm_for_each_lun(gn, lun, i)
> +		pr_info("%s: lun%8u\t%u\n",
> +					dev->name, i, lun->vlun.nr_free_blocks);
> +}
> +
> +static struct nvmm_type gennvm = {
> +	.name		= "gennvm",
> +	.version	= {0, 1, 0},
> +
> +	.register_mgr	= gennvm_register,
> +	.unregister_mgr	= gennvm_unregister,
> +
> +	.get_blk	= gennvm_get_blk,
> +	.put_blk	= gennvm_put_blk,
> +
> +	.submit_io	= gennvm_submit_io,
> +	.end_io		= gennvm_end_io,
> +	.erase_blk	= gennvm_erase_blk,
> +
> +	.get_lun	= gennvm_get_lun,
> +	.free_blocks_print = gennvm_free_blocks_print,
> +};
> +
> +static int __init gennvm_module_init(void)
> +{
> +	return nvm_register_mgr(&gennvm);
> +}
> +
> +static void gennvm_module_exit(void)
> +{
> +	nvm_unregister_mgr(&gennvm);
> +}
> +
> +module_init(gennvm_module_init);
> +module_exit(gennvm_module_exit);
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Block manager for Hybrid Open-Channel SSDs");
> diff --git a/drivers/lightnvm/gennvm.h b/drivers/lightnvm/gennvm.h
> new file mode 100644
> index 0000000..d23bd35
> --- /dev/null
> +++ b/drivers/lightnvm/gennvm.h
> @@ -0,0 +1,46 @@
> +/*
> + * Copyright: Matias Bjorling <mb@bjorling.me>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License version
> + * 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * General Public License for more details.
> + *
> + */
> +
> +#ifndef GENNVM_H_
> +#define GENNVM_H_
> +
> +#include <linux/module.h>
> +#include <linux/vmalloc.h>
> +
> +#include <linux/lightnvm.h>
> +
> +struct gen_lun {
> +	struct nvm_lun vlun;
> +
> +	int reserved_blocks;
> +	/* lun block lists */
> +	struct list_head used_list;	/* In-use blocks */
> +	struct list_head free_list;	/* Not used blocks i.e. released
> +					 * and ready for use
> +					 */
> +	struct list_head bb_list;	/* Bad blocks. Mutually exclusive with
> +					 * free_list and used_list
> +					 */
> +};
> +
> +struct gen_nvm {
> +	int nr_luns;
> +	struct gen_lun *luns;
> +};
> +
> +#define gennvm_for_each_lun(bm, lun, i) \
> +		for ((i) = 0, lun = &(bm)->luns[0]; \
> +			(i) < (bm)->nr_luns; (i)++, lun = &(bm)->luns[(i)])
> +
> +#endif /* GENNVM_H_ */
>