Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7aeacf98 authored by Jens Axboe's avatar Jens Axboe
Browse files

[BLOCK] blk_rq_map_sg: force clear termination bit 



Since blk_rq_map_sg() sets the termination bit at the end of the sg
table, we could see it prematurely on the next mapping unless we
force drivers to do a full sg_init_table() prior to each mapping. So
force clear the termination bit to avoid having to put that clear in
the driver for every mapping.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent ad0d4083

block/ll_rw_blk.c

+13 −1
Original line number Diff line number Diff line
@@ -1351,8 +1351,20 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, 
new_segment:

			if (!sg)

				sg = sglist;

			else

			else {

				/*

				 * If the driver previously mapped a shorter

				 * list, we could see a termination bit

				 * prematurely unless it fully inits the sg

				 * table on each mapping. We KNOW that there

				 * must be more entries here or the driver

				 * would be buggy, so force clear the

				 * termination bit to avoid doing a full

				 * sg_init_table() in drivers for each command.

				 */

				sg->page_link &= ~0x02;

				sg = sg_next(sg);

			}



			sg_set_page(sg, bvec->bv_page);

			sg->length = nbytes;