[PATCH 4.12 081/196] libnvdimm, btt: fix btt_rw_page not returning errors

[Greg Kroah-Hartman]

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

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

From: Vishal Verma <vishal.l.verma@xxxxxxxxx>

commit c13c43d54f2c6a3be1c675766778ac1ad8dfbfcc upstream.

btt_rw_page was not propagating errors frm btt_do_bvec, resulting in any
IO errors via the rw_page path going unnoticed. the pmem driver recently
fixed this in e10624f pmem: fail io-requests to known bad blocks
but same problem in BTT went neglected.

Fixes: 5212e11fde4d ("nd_btt: atomic sector updates")
Cc: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Signed-off-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/btt.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -1248,10 +1248,13 @@ static int btt_rw_page(struct block_devi
 		struct page *page, bool is_write)
 {
 	struct btt *btt = bdev->bd_disk->private_data;
+	int rc;
 
-	btt_do_bvec(btt, NULL, page, PAGE_SIZE, 0, is_write, sector);
-	page_endio(page, is_write, 0);
-	return 0;
+	rc = btt_do_bvec(btt, NULL, page, PAGE_SIZE, 0, is_write, sector);
+	if (rc == 0)
+		page_endio(page, is_write, 0);
+
+	return rc;
 }