lightnvm: specify target's logical address area

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 cause incorrect
information in the device's l2p table.

Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 67 insertions, 0 deletions

diff --git a/drivers/lightnvm/gennvm.c b/drivers/lightnvm/gennvm.c
index d65ec36a2231..d460b37bb016 100644
--- a/drivers/lightnvm/gennvm.c
+++ b/drivers/lightnvm/gennvm.c
@@ -20,6 +20,68 @@
 
 #include "gennvm.h"
 
+static int gennvm_get_area(struct nvm_dev *dev, sector_t *lba, sector_t len)
+{
+	struct gen_nvm *gn = dev->mp;
+	struct gennvm_area *area, *prev, *next;
+	sector_t begin = 0;
+	sector_t max_sectors = (dev->sec_size * dev->total_secs) >> 9;
+
+	if (len > max_sectors)
+		return -EINVAL;
+
+	area = kmalloc(sizeof(struct gennvm_area), GFP_KERNEL);
+	if (!area)
+		return -ENOMEM;
+
+	prev = NULL;
+
+	spin_lock(&dev->lock);
+	list_for_each_entry(next, &gn->area_list, list) {
+		if (begin + len > next->begin) {
+			begin = next->end;
+			prev = next;
+			continue;
+		}
+		break;
+	}
+
+	if ((begin + len) > max_sectors) {
+		spin_unlock(&dev->lock);
+		kfree(area);
+		return -EINVAL;
+	}
+
+	area->begin = *lba = begin;
+	area->end = begin + len;
+
+	if (prev) /* insert into sorted order */
+		list_add(&area->list, &prev->list);
+	else
+		list_add(&area->list, &gn->area_list);
+	spin_unlock(&dev->lock);
+
+	return 0;
+}
+
+static void gennvm_put_area(struct nvm_dev *dev, sector_t begin)
+{
+	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->begin != begin)
+			continue;
+
+		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;
@@ -229,6 +291,7 @@ 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);
@@ -465,6 +528,10 @@ 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)