Commit ce51c696 authored by Mikulas Patocka's avatar Mikulas Patocka
Browse files

dm-crypt: enable DM_TARGET_ATOMIC_WRITES 



Allow handling of bios with REQ_ATOMIC flag set.

Don't split these bios and fail them if they overrun the hard limit
"BIO_MAX_VECS << PAGE_SHIFT".

In order to simplify the code, this commit joins the logic that avoids
splitting emulated zone append bios with the logic that avoids
splitting atomic write bios.

Signed-off-by: default avatarJohn Garry <john.g.garry@oracle.com>
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Tested-by: default avatarJohn Garry <john.g.garry@oracle.com>
parent de67c139

drivers/md/dm-crypt.c

+24 −15
Original line number Diff line number Diff line
@@ -254,22 +254,15 @@ static unsigned int max_write_size = 0; 
module_param(max_write_size, uint, 0644);

MODULE_PARM_DESC(max_write_size, "Maximum size of a write request");



static unsigned get_max_request_sectors(struct dm_target *ti, struct bio *bio)

static unsigned get_max_request_sectors(struct dm_target *ti, struct bio *bio, bool no_split)

{

	struct crypt_config *cc = ti->private;

	unsigned val, sector_align;

	bool wrt = op_is_write(bio_op(bio));



	if (wrt) {

		/*

		 * For zoned devices, splitting write operations creates the

		 * risk of deadlocking queue freeze operations with zone write

		 * plugging BIO work when the reminder of a split BIO is

		 * issued. So always allow the entire BIO to proceed.

		 */

		if (ti->emulate_zone_append)

			return bio_sectors(bio);



	if (no_split) {

		val = -1;

	} else if (wrt) {

		val = min_not_zero(READ_ONCE(max_write_size),

				   DM_CRYPT_DEFAULT_MAX_WRITE_SIZE);

	} else {
@@ -3462,6 +3455,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio) 
	struct dm_crypt_io *io;

	struct crypt_config *cc = ti->private;

	unsigned max_sectors;

	bool no_split;



	/*

	 * If bio is REQ_PREFLUSH or REQ_OP_DISCARD, just bypass crypt queues.
@@ -3479,10 +3473,20 @@ static int crypt_map(struct dm_target *ti, struct bio *bio) 


	/*

	 * Check if bio is too large, split as needed.

	 *

	 * For zoned devices, splitting write operations creates the

	 * risk of deadlocking queue freeze operations with zone write

	 * plugging BIO work when the reminder of a split BIO is

	 * issued. So always allow the entire BIO to proceed.

	 */

	max_sectors = get_max_request_sectors(ti, bio);

	if (unlikely(bio_sectors(bio) > max_sectors))

	no_split = (ti->emulate_zone_append && op_is_write(bio_op(bio))) ||

		   (bio->bi_opf & REQ_ATOMIC);

	max_sectors = get_max_request_sectors(ti, bio, no_split);

	if (unlikely(bio_sectors(bio) > max_sectors)) {

		if (unlikely(no_split))

			return DM_MAPIO_KILL;

		dm_accept_partial_bio(bio, max_sectors);

	}



	/*

	 * Ensure that bio is a multiple of internal sector encryption size
@@ -3728,15 +3732,20 @@ static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits) 
	if (ti->emulate_zone_append)

		limits->max_hw_sectors = min(limits->max_hw_sectors,

					     BIO_MAX_VECS << PAGE_SECTORS_SHIFT);



	limits->atomic_write_hw_unit_max = min(limits->atomic_write_hw_unit_max,

					       BIO_MAX_VECS << PAGE_SHIFT);

	limits->atomic_write_hw_max = min(limits->atomic_write_hw_max,

					  BIO_MAX_VECS << PAGE_SHIFT);

}



static struct target_type crypt_target = {

	.name   = "crypt",

	.version = {1, 28, 0},

	.version = {1, 29, 0},

	.module = THIS_MODULE,

	.ctr    = crypt_ctr,

	.dtr    = crypt_dtr,

	.features = DM_TARGET_ZONED_HM,

	.features = DM_TARGET_ZONED_HM | DM_TARGET_ATOMIC_WRITES,

	.report_zones = crypt_report_zones,

	.map    = crypt_map,

	.status = crypt_status,