md: add a new callback pers->bitmap_sector()

This callback will be used in raid5 to convert io ranges from array to
bitmap.

Signed-off-by: Yu Kuai <[email protected]>
Reviewed-by: Xiao Ni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Song Liu <[email protected]>

Author: YuKuai-huawei

drivers/md/md.h

@@ -746,6 +746,9 @@ struct md_personality
 	void *(*takeover) (struct mddev *mddev);
 	/* Changes the consistency policy of an active array. */
 	int (*change_consistency_policy)(struct mddev *mddev, const char *buf);
+	/* convert io ranges from array to bitmap */
+	void (*bitmap_sector)(struct mddev *mddev, sector_t *offset,
+			      unsigned long *sectors);
 };
 
 struct md_sysfs_entry {