[mirror_ubuntu-zesty-kernel.git] / include / linux / dax.h

#ifndef _LINUX_DAX_H
#define _LINUX_DAX_H

#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/radix-tree.h>
#include <asm/pgtable.h>

struct iomap_ops;

/*
 * We use lowest available bit in exceptional entry for locking, one bit for
 * the entry size (PMD) and two more to tell us if the entry is a huge zero
 * page (HZP) or an empty entry that is just used for locking.  In total four
 * special bits.
 *
 * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and
 * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
 * block allocation.
 */
#define RADIX_DAX_SHIFT	(RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
#define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
#define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
#define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
#define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))

static inline unsigned long dax_radix_sector(void *entry)
{
	return (unsigned long)entry >> RADIX_DAX_SHIFT;
}

static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
{
	return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags |
			((unsigned long)sector << RADIX_DAX_SHIFT) |
			RADIX_DAX_ENTRY_LOCK);
}

ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
		struct iomap_ops *ops);
int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
			struct iomap_ops *ops);
int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
void dax_wake_mapping_entry_waiter(struct address_space *mapping,
		pgoff_t index, void *entry, bool wake_all);

#ifdef CONFIG_FS_DAX
struct page *read_dax_sector(struct block_device *bdev, sector_t n);
int __dax_zero_page_range(struct block_device *bdev, sector_t sector,
		unsigned int offset, unsigned int length);
#else
static inline struct page *read_dax_sector(struct block_device *bdev,
		sector_t n)
{
	return ERR_PTR(-ENXIO);
}
static inline int __dax_zero_page_range(struct block_device *bdev,
		sector_t sector, unsigned int offset, unsigned int length)
{
	return -ENXIO;
}
#endif

#ifdef CONFIG_FS_DAX_PMD
static inline unsigned int dax_radix_order(void *entry)
{
	if ((unsigned long)entry & RADIX_DAX_PMD)
		return PMD_SHIFT - PAGE_SHIFT;
	return 0;
}
int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
		pmd_t *pmd, unsigned int flags, struct iomap_ops *ops);
#else
static inline unsigned int dax_radix_order(void *entry)
{
	return 0;
}
static inline int dax_iomap_pmd_fault(struct vm_area_struct *vma,
		unsigned long address, pmd_t *pmd, unsigned int flags,
		struct iomap_ops *ops)
{
	return VM_FAULT_FALLBACK;
}
#endif
int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);

static inline bool vma_is_dax(struct vm_area_struct *vma)
{
	return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
}

static inline bool dax_mapping(struct address_space *mapping)
{
	return mapping->host && IS_DAX(mapping->host);
}

struct writeback_control;
int dax_writeback_mapping_range(struct address_space *mapping,
		struct block_device *bdev, struct writeback_control *wbc);
#endif
Commit	Line	Data
c94c2acf MW	1	#ifndef _LINUX_DAX_H
	2	#define _LINUX_DAX_H
	3
	4	#include <linux/fs.h>
	5	#include <linux/mm.h>
4f622938	6	#include <linux/radix-tree.h>
c94c2acf MW	7	#include <asm/pgtable.h>
c94c2acf MW	8
a254e568 CH	9	struct iomap_ops;
a254e568 CH	10
fa28f729	11	/*
642261ac RZ	12	* We use lowest available bit in exceptional entry for locking, one bit for
	13	* the entry size (PMD) and two more to tell us if the entry is a huge zero
	14	* page (HZP) or an empty entry that is just used for locking. In total four
	15	* special bits.
	16	*
	17	* If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and
	18	* EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
	19	* block allocation.
fa28f729	20	*/
642261ac	21	#define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
e804315d	22	#define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
642261ac RZ	23	#define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
	24	#define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
	25	#define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))
fa28f729	26
642261ac RZ	27	static inline unsigned long dax_radix_sector(void *entry)
	28	{
	29	return (unsigned long)entry >> RADIX_DAX_SHIFT;
	30	}
	31
	32	static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
	33	{
	34	return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY \| flags \|
	35	((unsigned long)sector << RADIX_DAX_SHIFT) \|
	36	RADIX_DAX_ENTRY_LOCK);
	37	}
e804315d	38
11c59c92	39	ssize_t dax_iomap_rw(struct kiocb iocb, struct iov_iter iter,
a254e568	40	struct iomap_ops *ops);
11c59c92	41	int dax_iomap_fault(struct vm_area_struct vma, struct vm_fault vmf,
a7d73fe6	42	struct iomap_ops *ops);
ac401cc7 JK	43	int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
ac401cc7 JK	44	void dax_wake_mapping_entry_waiter(struct address_space *mapping,
63e95b5c	45	pgoff_t index, void *entry, bool wake_all);
d1a5f2b4 DW	46
	47	#ifdef CONFIG_FS_DAX
	48	struct page read_dax_sector(struct block_device bdev, sector_t n);
679c8bd3 CH	49	int __dax_zero_page_range(struct block_device *bdev, sector_t sector,
679c8bd3 CH	50	unsigned int offset, unsigned int length);
d1a5f2b4 DW	51	#else
	52	static inline struct page read_dax_sector(struct block_device bdev,
	53	sector_t n)
	54	{
	55	return ERR_PTR(-ENXIO);
	56	}
679c8bd3 CH	57	static inline int __dax_zero_page_range(struct block_device *bdev,
	58	sector_t sector, unsigned int offset, unsigned int length)
	59	{
	60	return -ENXIO;
	61	}
d1a5f2b4 DW	62	#endif
d1a5f2b4 DW	63
642261ac RZ	64	#ifdef CONFIG_FS_DAX_PMD
	65	static inline unsigned int dax_radix_order(void *entry)
	66	{
	67	if ((unsigned long)entry & RADIX_DAX_PMD)
	68	return PMD_SHIFT - PAGE_SHIFT;
	69	return 0;
	70	}
	71	int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
	72	pmd_t pmd, unsigned int flags, struct iomap_ops ops);
	73	#else
	74	static inline unsigned int dax_radix_order(void *entry)
	75	{
	76	return 0;
	77	}
	78	static inline int dax_iomap_pmd_fault(struct vm_area_struct *vma,
	79	unsigned long address, pmd_t *pmd, unsigned int flags,
	80	struct iomap_ops *ops)
	81	{
	82	return VM_FAULT_FALLBACK;
	83	}
	84	#endif
c94c2acf	85	int dax_pfn_mkwrite(struct vm_area_struct , struct vm_fault );
c94c2acf	86
4897c765 MW	87	static inline bool vma_is_dax(struct vm_area_struct *vma)
	88	{
	89	return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
	90	}
f9fe48be RZ	91
	92	static inline bool dax_mapping(struct address_space *mapping)
	93	{
	94	return mapping->host && IS_DAX(mapping->host);
	95	}
7f6d5b52 RZ	96
	97	struct writeback_control;
	98	int dax_writeback_mapping_range(struct address_space *mapping,
	99	struct block_device bdev, struct writeback_control wbc);
c94c2acf	100	#endif