[PATCH 2/6] block: Add npo2_zone_setup callback to block device fops

[Pankaj Raghav <p.raghav@samsung.com>]

A new fops is added to block device which will be used to setup the
necessary hooks when a non-power_of_2 zone size is detected in a zoned
device.

This fops will be called as a part of blk_revalidate_disk_zones.

The primary use case for this callback is to deal with zoned devices
that does not have a power_of_2 zone size such as ZNS drives.For e.g,
the current NVMe ZNS specification does not require zone size to be
power_of_2 but the linux block layer still expects a all zoned device to
have a power_of_2 zone size.

Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
 block/blk-zoned.c      | 3 +++
 include/linux/blkdev.h | 1 +
 2 files changed, 4 insertions(+)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 602bef54c813..d3d821797559 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -575,6 +575,9 @@ int blk_revalidate_disk_zones(struct gendisk *disk,
 	if (!get_capacity(disk))
 		return -EIO;
 
+	if (disk->fops->npo2_zone_setup)
+		disk->fops->npo2_zone_setup(disk);
+
 	/*
 	 * Ensure that all memory allocations in this context are done as if
 	 * GFP_NOIO was specified.
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a12c031af887..08cf039c1622 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1472,6 +1472,7 @@ struct block_device_operations {
 	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
 	int (*report_zones)(struct gendisk *, sector_t sector,
 			unsigned int nr_zones, report_zones_cb cb, void *data);
+	void (*npo2_zone_setup)(struct gendisk *disk);
 	char *(*devnode)(struct gendisk *disk, umode_t *mode);
 	/* returns the length of the identifier or a negative errno: */
 	int (*get_unique_id)(struct gendisk *disk, u8 id[16],
-- 
2.25.1