libnvdimm, btt: ensure that flags were also unchanged during a map_read
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>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index bb816bc..15d1b07 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -1032,6 +1032,7 @@
*/
while (1) {
u32 new_map;
+ int new_t, new_e;
if (t_flag) {
zero_fill_data(page, off, cur_len);
@@ -1050,15 +1051,18 @@
*/
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);