block: Introduce bio_straddles_zones() and bio_offset_from_zone_start()

Implement the inline helper functions bio_straddles_zones() and
bio_offset_from_zone_start() to respectively test if a BIO crosses a
zone boundary (the start sector and last sector belong to different
zones) and to obtain the offset of a BIO from the start sector of its
target zone.

Signed-off-by: Damien Le Moal <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Tested-by: Hans Holmberg <[email protected]>
Tested-by: Dennis Maisenbacher <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: damien-lemoal

include/linux/blkdev.h

@@ -853,6 +853,13 @@ static inline unsigned int bio_zone_no(struct bio *bio)
 	return disk_zone_no(bio->bi_bdev->bd_disk, bio->bi_iter.bi_sector);
 }
 
+static inline bool bio_straddles_zones(struct bio *bio)
+{
+	return bio_sectors(bio) &&
+		bio_zone_no(bio) !=
+		disk_zone_no(bio->bi_bdev->bd_disk, bio_end_sector(bio) - 1);
+}
+
 static inline unsigned int bio_zone_is_seq(struct bio *bio)
 {
 	return disk_zone_is_seq(bio->bi_bdev->bd_disk, bio->bi_iter.bi_sector);
@@ -1328,6 +1335,12 @@ static inline sector_t bdev_offset_from_zone_start(struct block_device *bdev,
 	return sector & (bdev_zone_sectors(bdev) - 1);
 }
 
+static inline sector_t bio_offset_from_zone_start(struct bio *bio)
+{
+	return bdev_offset_from_zone_start(bio->bi_bdev,
+					   bio->bi_iter.bi_sector);
+}
+
 static inline bool bdev_is_zone_start(struct block_device *bdev,
 				      sector_t sector)
 {