block: simplify blkdev_nr_zones

Simplify the arguments to blkdev_nr_zones by passing a gendisk instead
of the block_device and capacity.  This also removes the need for
__blkdev_nr_zones as all callers are outside the fast path and can
deal with the additional branch.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-zoned.c

@@ -70,30 +70,20 @@ void __blk_req_zone_write_unlock(struct request *rq)
 }
 EXPORT_SYMBOL_GPL(__blk_req_zone_write_unlock);
 
-static inline unsigned int __blkdev_nr_zones(struct request_queue *q,
-					     sector_t nr_sectors)
-{
-	sector_t zone_sectors = blk_queue_zone_sectors(q);
-
-	return (nr_sectors + zone_sectors - 1) >> ilog2(zone_sectors);
-}
-
 /**
  * blkdev_nr_zones - Get number of zones
- * @bdev:	Target block device
+ * @disk:	Target gendisk
  *
- * Description:
- *    Return the total number of zones of a zoned block device.
- *    For a regular block device, the number of zones is always 0.
+ * Return the total number of zones of a zoned block device.  For a block
+ * device without zone capabilities, the number of zones is always 0.
  */
-unsigned int blkdev_nr_zones(struct block_device *bdev)
+unsigned int blkdev_nr_zones(struct gendisk *disk)
 {
-	struct request_queue *q = bdev_get_queue(bdev);
+	sector_t zone_sectors = blk_queue_zone_sectors(disk->queue);
 
-	if (!blk_queue_is_zoned(q))
+	if (!blk_queue_is_zoned(disk->queue))
 		return 0;
-
-	return __blkdev_nr_zones(q, get_capacity(bdev->bd_disk));
+	return (get_capacity(disk) + zone_sectors - 1) >> ilog2(zone_sectors);
 }
 EXPORT_SYMBOL_GPL(blkdev_nr_zones);
 
@@ -447,7 +437,7 @@ static int blk_update_zone_info(struct gendisk *disk, unsigned int nr_zones,
 int blk_revalidate_disk_zones(struct gendisk *disk)
 {
 	struct request_queue *q = disk->queue;
-	unsigned int nr_zones = __blkdev_nr_zones(q, get_capacity(disk));
+	unsigned int nr_zones = blkdev_nr_zones(disk);
 	struct blk_revalidate_zone_args args = { .disk = disk };
 	int ret = 0;
 

block/ioctl.c

@@ -512,7 +512,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 	case BLKGETZONESZ:
 		return put_uint(arg, bdev_zone_sectors(bdev));
 	case BLKGETNRZONES:
-		return put_uint(arg, blkdev_nr_zones(bdev));
+		return put_uint(arg, blkdev_nr_zones(bdev->bd_disk));
 	case HDIO_GETGEO:
 		return blkdev_getgeo(bdev, argp);
 	case BLKRAGET:

drivers/md/dm-zoned-target.c

@@ -727,7 +727,7 @@ static int dmz_get_zoned_device(struct dm_target *ti, char *path)
 	dev->zone_nr_blocks = dmz_sect2blk(dev->zone_nr_sectors);
 	dev->zone_nr_blocks_shift = ilog2(dev->zone_nr_blocks);
 
-	dev->nr_zones = blkdev_nr_zones(dev->bdev);
+	dev->nr_zones = blkdev_nr_zones(dev->bdev->bd_disk);
 
 	dmz->dev = dev;
 

include/linux/blkdev.h

@@ -357,8 +357,7 @@ typedef int (*report_zones_cb)(struct blk_zone *zone, unsigned int idx,
 #define BLK_ALL_ZONES  ((unsigned int)-1)
 int blkdev_report_zones(struct block_device *bdev, sector_t sector,
 			unsigned int nr_zones, report_zones_cb cb, void *data);
-
-extern unsigned int blkdev_nr_zones(struct block_device *bdev);
+unsigned int blkdev_nr_zones(struct gendisk *disk);
 extern int blkdev_zone_mgmt(struct block_device *bdev, enum req_opf op,
 			    sector_t sectors, sector_t nr_sectors,
 			    gfp_t gfp_mask);
@@ -371,7 +370,7 @@ extern int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode,
 
 #else /* CONFIG_BLK_DEV_ZONED */
 
-static inline unsigned int blkdev_nr_zones(struct block_device *bdev)
+static inline unsigned int blkdev_nr_zones(struct gendisk *disk)
 {
 	return 0;
 }