dax: Define DAX lock bit for radix tree exceptional entry

#include <linux/pfn_t.h>

#include <linux/sizes.h>

#define RADIX_DAX_MASK	0xf

#define RADIX_DAX_SHIFT	4

#define RADIX_DAX_PTE  (0x4 | RADIX_TREE_EXCEPTIONAL_ENTRY)

#define RADIX_DAX_PMD  (0x8 | RADIX_TREE_EXCEPTIONAL_ENTRY)

#define RADIX_DAX_TYPE(entry) ((unsigned long)entry & RADIX_DAX_MASK)

/*

 * We use lowest available bit in exceptional entry for locking, other two

 * bits to determine entry type. In total 3 special bits.

 */

#define RADIX_DAX_SHIFT	(RADIX_TREE_EXCEPTIONAL_SHIFT + 3)

#define RADIX_DAX_PTE (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))

#define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))

#define RADIX_DAX_TYPE_MASK (RADIX_DAX_PTE | RADIX_DAX_PMD)

#define RADIX_DAX_TYPE(entry) ((unsigned long)entry & RADIX_DAX_TYPE_MASK)

#define RADIX_DAX_SECTOR(entry) (((unsigned long)entry >> RADIX_DAX_SHIFT))

#define RADIX_DAX_ENTRY(sector, pmd) ((void *)((unsigned long)sector << \

		RADIX_DAX_SHIFT | (pmd ? RADIX_DAX_PMD : RADIX_DAX_PTE)))

		RADIX_DAX_SHIFT | (pmd ? RADIX_DAX_PMD : RADIX_DAX_PTE) | \

		RADIX_TREE_EXCEPTIONAL_ENTRY))

static long dax_map_atomic(struct block_device *bdev, struct blk_dax_ctl *dax)

{

#include <linux/mm.h>

#include <asm/pgtable.h>

/* We use lowest available exceptional entry bit for locking */

#define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)

ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,

		  get_block_t, dio_iodone_t, int flags);

int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);