[PATCH v4 4/6] libnvdimm/namespace: Validate namespace size when creating a new namespace.

["Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>]

Kernel should validate the namespace size against SUBSECTION_SIZE rather than
PAGE_SIZE. blk namespace continues to use old rule so that the new kernel don't
break the creation of blk namespaces.

Use the new helper arch_namespace_align_size() so that architecture specific
restrictions are also taken care of.

kernel log will contain the below details
[  939.620064] nd namespace0.3: 1071644672 is not 16384K aligned

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 drivers/nvdimm/namespace_devs.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 0e2c90730ce3..e318566ae135 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -891,6 +891,17 @@ static int grow_dpa_allocation(struct nd_region *nd_region,
 	return 0;
 }
 
+static unsigned long nvdimm_validate_namespace_size(struct nd_region *nd_region,
+		unsigned long size, unsigned long align_size)
+{
+	u32 remainder;
+
+	div_u64_rem(size, align_size * nd_region->ndr_mappings, &remainder);
+	if (remainder)
+		return align_size * nd_region->ndr_mappings;
+	return 0;
+}
+
 static void nd_namespace_pmem_set_resource(struct nd_region *nd_region,
 		struct nd_namespace_pmem *nspm, resource_size_t size)
 {
@@ -945,11 +956,13 @@ static ssize_t __size_store(struct device *dev, unsigned long long val)
 {
 	resource_size_t allocated = 0, available = 0;
 	struct nd_region *nd_region = to_nd_region(dev->parent);
+	unsigned long align_size = arch_namespace_align_size();
 	struct nd_namespace_common *ndns = to_ndns(dev);
 	struct nd_mapping *nd_mapping;
 	struct nvdimm_drvdata *ndd;
 	struct nd_label_id label_id;
-	u32 flags = 0, remainder;
+	unsigned long map_size;
+	u32 flags = 0;
 	int rc, i, id = -1;
 	u8 *uuid = NULL;
 
@@ -967,6 +980,8 @@ static ssize_t __size_store(struct device *dev, unsigned long long val)
 		uuid = nsblk->uuid;
 		flags = NSLABEL_FLAG_LOCAL;
 		id = nsblk->id;
+		/* Let's not break blk region */
+		align_size = PAGE_SIZE;
 	}
 
 	/*
@@ -980,10 +995,9 @@ static ssize_t __size_store(struct device *dev, unsigned long long val)
 		return -ENXIO;
 	}
 
-	div_u64_rem(val, PAGE_SIZE * nd_region->ndr_mappings, &remainder);
-	if (remainder) {
-		dev_dbg(dev, "%llu is not %ldK aligned\n", val,
-				(PAGE_SIZE * nd_region->ndr_mappings) / SZ_1K);
+	map_size = nvdimm_validate_namespace_size(nd_region, val, align_size);
+	if (map_size) {
+		dev_err(dev, "%llu is not %ldK aligned\n", val, map_size / SZ_1K);
 		return -EINVAL;
 	}
 
-- 
2.24.1
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