[RFC PATCH 1/2] lightnvm: specify target's logical address area

[Wenwei Tao <ww.tao0320@gmail.com>]

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@gmail.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;
+	int page_size = dev->sec_size * dev->sec_per_pg;
+	sector_t max = page_size * dev->total_pages >> 9;
+
+	if (size > max)
+		return -EINVAL;
+	area = kmalloc(sizeof(*area), GFP_KERNEL);
+	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) {
+		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;
+	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;
+	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);
+	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;
 };
 
-- 
1.8.3.1