[mirror_ubuntu-artful-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);
int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index);
int dax_invalidate_mapping_entry_sync(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	43	int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
c6dcf52c JK	44	int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index);
	45	int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
	46	pgoff_t index);
ac401cc7	47	void dax_wake_mapping_entry_waiter(struct address_space *mapping,
63e95b5c	48	pgoff_t index, void *entry, bool wake_all);
d1a5f2b4 DW	49
	50	#ifdef CONFIG_FS_DAX
	51	struct page read_dax_sector(struct block_device bdev, sector_t n);
679c8bd3 CH	52	int __dax_zero_page_range(struct block_device *bdev, sector_t sector,
679c8bd3 CH	53	unsigned int offset, unsigned int length);
d1a5f2b4 DW	54	#else
	55	static inline struct page read_dax_sector(struct block_device bdev,
	56	sector_t n)
	57	{
	58	return ERR_PTR(-ENXIO);
	59	}
679c8bd3 CH	60	static inline int __dax_zero_page_range(struct block_device *bdev,
	61	sector_t sector, unsigned int offset, unsigned int length)
	62	{
	63	return -ENXIO;
	64	}
d1a5f2b4 DW	65	#endif
d1a5f2b4 DW	66
642261ac RZ	67	#ifdef CONFIG_FS_DAX_PMD
	68	static inline unsigned int dax_radix_order(void *entry)
	69	{
	70	if ((unsigned long)entry & RADIX_DAX_PMD)
	71	return PMD_SHIFT - PAGE_SHIFT;
	72	return 0;
	73	}
	74	int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
	75	pmd_t pmd, unsigned int flags, struct iomap_ops ops);
	76	#else
	77	static inline unsigned int dax_radix_order(void *entry)
	78	{
	79	return 0;
	80	}
	81	static inline int dax_iomap_pmd_fault(struct vm_area_struct *vma,
	82	unsigned long address, pmd_t *pmd, unsigned int flags,
	83	struct iomap_ops *ops)
	84	{
	85	return VM_FAULT_FALLBACK;
	86	}
	87	#endif
c94c2acf	88	int dax_pfn_mkwrite(struct vm_area_struct , struct vm_fault );
c94c2acf	89
4897c765 MW	90	static inline bool vma_is_dax(struct vm_area_struct *vma)
	91	{
	92	return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
	93	}
f9fe48be RZ	94
	95	static inline bool dax_mapping(struct address_space *mapping)
	96	{
	97	return mapping->host && IS_DAX(mapping->host);
	98	}
7f6d5b52 RZ	99
	100	struct writeback_control;
	101	int dax_writeback_mapping_range(struct address_space *mapping,
	102	struct block_device bdev, struct writeback_control wbc);
c94c2acf	103	#endif