block: add a new helper bdev_{is_zone_start, offset_from_zone_start}

Instead of open coding to check for zone start, add a helper to improve
readability and store the logic in one place.

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230110143635.77300-3-p.raghav@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-core.c

@@ -570,7 +570,7 @@ static inline blk_status_t blk_check_zone_append(struct request_queue *q,
 		return BLK_STS_NOTSUPP;
 
 	/* The bio sector must point to the start of a sequential zone */
-	if (bio->bi_iter.bi_sector & (bdev_zone_sectors(bio->bi_bdev) - 1) ||
+	if (!bdev_is_zone_start(bio->bi_bdev, bio->bi_iter.bi_sector) ||
 	    !bio_zone_is_seq(bio))
 		return BLK_STS_IOERR;
 

block/blk-zoned.c

@@ -277,10 +277,10 @@ int blkdev_zone_mgmt(struct block_device *bdev, enum req_op op,
 		return -EINVAL;
 
 	/* Check alignment (handle eventual smaller last zone) */
-	if (sector & (zone_sectors - 1))
+	if (!bdev_is_zone_start(bdev, sector))
 		return -EINVAL;
 
-	if ((nr_sectors & (zone_sectors - 1)) && end_sector != capacity)
+	if (!bdev_is_zone_start(bdev, nr_sectors) && end_sector != capacity)
 		return -EINVAL;
 
 	/*

include/linux/blkdev.h

@@ -1306,6 +1306,18 @@ static inline sector_t bdev_zone_sectors(struct block_device *bdev)
 	return q->limits.chunk_sectors;
 }
 
+static inline sector_t bdev_offset_from_zone_start(struct block_device *bdev,
+						   sector_t sector)
+{
+	return sector & (bdev_zone_sectors(bdev) - 1);
+}
+
+static inline bool bdev_is_zone_start(struct block_device *bdev,
+				      sector_t sector)
+{
+	return bdev_offset_from_zone_start(bdev, sector) == 0;
+}
+
 static inline int queue_dma_alignment(const struct request_queue *q)
 {
 	return q ? q->limits.dma_alignment : 511;