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Commit 1398199d authored by Vishal Verma's avatar Vishal Verma Committed by Dan Williams
Browse files

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: default avatarVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 0595d539

drivers/nvdimm/btt.c

+7 −3
Original line number Diff line number Diff line
@@ -1032,6 +1032,7 @@ 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);
@@ -1050,15 +1051,18 @@ 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);