dm-zone: Use bdev_*() helper functions where applicable

Improve code readability by using bdev_is_zone_aligned() and
bdev_offset_from_zone_start() where applicable. No functionality
has been changed.

This patch is a reworked version of a patch from Pankaj Raghav.

See also https://lore.kernel.org/linux-block/20220923173618.6899-11-p.raghav@samsung.com/.

Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

Author: bvanassche

drivers/md/dm-table.c

@@ -256,7 +256,7 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 	if (bdev_is_zoned(bdev)) {
 		unsigned int zone_sectors = bdev_zone_sectors(bdev);
 
-		if (start & (zone_sectors - 1)) {
+		if (!bdev_is_zone_aligned(bdev, start)) {
 			DMERR("%s: start=%llu not aligned to h/w zone size %u of %pg",
 			      dm_device_name(ti->table->md),
 			      (unsigned long long)start,
@@ -273,7 +273,7 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 		 * devices do not end up with a smaller zone in the middle of
 		 * the sector range.
 		 */
-		if (len & (zone_sectors - 1)) {
+		if (!bdev_is_zone_aligned(bdev, len)) {
 			DMERR("%s: len=%llu not aligned to h/w zone size %u of %pg",
 			      dm_device_name(ti->table->md),
 			      (unsigned long long)len,

drivers/md/dm-zone.c

@@ -463,9 +463,9 @@ void dm_zone_endio(struct dm_io *io, struct bio *clone)
 	 */
 	if (clone->bi_status == BLK_STS_OK &&
 	    bio_op(clone) == REQ_OP_ZONE_APPEND) {
-		sector_t mask = bdev_zone_sectors(disk->part0) - 1;
-
-		orig_bio->bi_iter.bi_sector += clone->bi_iter.bi_sector & mask;
+		orig_bio->bi_iter.bi_sector +=
+			bdev_offset_from_zone_start(disk->part0,
+						    clone->bi_iter.bi_sector);
 	}
 
 	return;

include/linux/blkdev.h

@@ -1419,6 +1419,13 @@ static inline bool bdev_is_zone_start(struct block_device *bdev,
 	return bdev_offset_from_zone_start(bdev, sector) == 0;
 }
 
+/* Check whether @sector is a multiple of the zone size. */
+static inline bool bdev_is_zone_aligned(struct block_device *bdev,
+					sector_t sector)
+{
+	return bdev_is_zone_start(bdev, sector);
+}
+
 /**
  * bdev_zone_is_seq - check if a sector belongs to a sequential write zone
  * @bdev:	block device to check