[PATCH 08/16] btrfs: zoned: add generic btrfs helpers for zoned devices

[Pankaj Raghav]

Add helpers to calculate alignment, round up and round down
for zoned devices. These helpers encapsulates the necessary handling for
power_of_2 and non-power_of_2 zone sizes. Optimized calculations are
performed for zone sizes that are power_of_2 with log and shifts.

btrfs_zoned_is_aligned() is added instead of reusing bdev_zone_aligned()
helper is due to some use cases in btrfs where zone alignment is checked
before having access to the underlying block device such as in this
function: btrfs_load_block_group_zone_info().

Reviewed-by: Luis Chamberlain <mcgrof at kernel.org>
Signed-off-by: Pankaj Raghav <p.raghav at samsung.com>
---
 fs/btrfs/zoned.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 49317524e9a6..b9c435961361 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -9,6 +9,7 @@
 #include "disk-io.h"
 #include "block-group.h"
 #include "btrfs_inode.h"
+#include "misc.h"
 
 /*
  * Block groups with more than this value (percents) of unusable space will be
@@ -34,6 +35,33 @@ struct btrfs_zoned_device_info {
 	u32 sb_zone_location[BTRFS_SUPER_MIRROR_MAX];
 };
 
+static inline bool btrfs_zoned_is_aligned(u64 pos, u64 zone_size)
+{
+	u64 remainder = 0;
+
+	if (is_power_of_two_u64(zone_size))
+		return IS_ALIGNED(pos, zone_size);
+
+	div64_u64_rem(pos, zone_size, &remainder);
+	return remainder == 0;
+}
+
+static inline u64 btrfs_zoned_roundup(u64 pos, u64 zone_size)
+{
+	if (is_power_of_two_u64(zone_size))
+		return ALIGN(pos, zone_size);
+
+	return roundup(pos, zone_size);
+}
+
+static inline u64 btrfs_zoned_rounddown(u64 pos, u64 zone_size)
+{
+	if (is_power_of_two_u64(zone_size))
+		return round_down(pos, zone_size);
+
+	return rounddown(pos, zone_size);
+}
+
 #ifdef CONFIG_BLK_DEV_ZONED
 int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 		       struct blk_zone *zone);
-- 
2.25.1