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[3/6] btt: ensure that flags were also unchanged during a map_read

Message ID 20170714221148.11232-4-vishal.l.verma@intel.com (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Verma, Vishal L July 14, 2017, 10:11 p.m. UTC 
In btt_map_read, we read the map twice to make sure that the map entry
didn't change after we added it to the read tracking table. In
anticipation of expanding the use of the error bit, also make sure that
the error and zero flags are constant across the two map reads.

Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 drivers/nvdimm/btt.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index 3aa6bc0..304dac4 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -1031,6 +1031,7 @@  static int btt_read_pg(struct btt *btt, struct bio_integrity_payload *bip,
 		 */
 		while (1) {
 			u32 new_map;
+			int new_t, new_e;
 
 			if (t_flag) {
 				zero_fill_data(page, off, cur_len);
@@ -1049,15 +1050,18 @@  static int btt_read_pg(struct btt *btt, struct bio_integrity_payload *bip,
 			 */
 			barrier();
 
-			ret = btt_map_read(arena, premap, &new_map, &t_flag,
-						&e_flag, NVDIMM_IO_ATOMIC);
+			ret = btt_map_read(arena, premap, &new_map, &new_t,
+						&new_e, NVDIMM_IO_ATOMIC);
 			if (ret)
 				goto out_rtt;
 
-			if (postmap == new_map)
+			if ((postmap == new_map) && (t_flag == new_t) &&
+					(e_flag == new_e))
 				break;
 
 			postmap = new_map;
+			t_flag = new_t;
+			e_flag = new_e;
 		}
 
 		ret = btt_data_read(arena, page, off, postmap, cur_len);