[PATCH 4.9 061/125] libnvdimm: fix badblock range handling of ARS range

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Toshi Kani <toshi.kani@xxxxxxx>

commit 4e3f0701f25ab194c5362576b1146a1e6cc6c2e7 upstream.

__add_badblock_range() does not account sector alignment when
it sets 'num_sectors'.  Therefore, an ARS error record range
spanning across two sectors is set to a single sector length,
which leaves the 2nd sector unprotected.

Change __add_badblock_range() to set 'num_sectors' properly.

Fixes: 0caeef63e6d2 ("libnvdimm: Add a poison list and export badblocks")
Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
Reviewed-by: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/nvdimm/core.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -450,14 +450,15 @@ static void set_badblock(struct badblock
 static void __add_badblock_range(struct badblocks *bb, u64 ns_offset, u64 len)
 {
 	const unsigned int sector_size = 512;
-	sector_t start_sector;
+	sector_t start_sector, end_sector;
 	u64 num_sectors;
 	u32 rem;
 
 	start_sector = div_u64(ns_offset, sector_size);
-	num_sectors = div_u64_rem(len, sector_size, &rem);
+	end_sector = div_u64_rem(ns_offset + len, sector_size, &rem);
 	if (rem)
-		num_sectors++;
+		end_sector++;
+	num_sectors = end_sector - start_sector;
 
 	if (unlikely(num_sectors > (u64)INT_MAX)) {
 		u64 remaining = num_sectors;