LXR linux/include/linux/dax.h

   1#ifndef _LINUX_DAX_H
   2#define _LINUX_DAX_H
   3
   4#include <linux/fs.h>
   5#include <linux/mm.h>
   6#include <linux/radix-tree.h>
   7#include <asm/pgtable.h>
   8
   9struct iomap_ops;
  10
  11/*
  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.
  20 */
  21#define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
  22#define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
  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))
  26
  27static inline unsigned long dax_radix_sector(void *entry)
  28{
  29        return (unsigned long)entry >> RADIX_DAX_SHIFT;
  30}
  31
  32static 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}
  38
  39ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
  40                struct iomap_ops *ops);
  41int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
  42                        struct iomap_ops *ops);
  43int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
  44int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index);
  45int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
  46                                      pgoff_t index);
  47void dax_wake_mapping_entry_waiter(struct address_space *mapping,
  48                pgoff_t index, void *entry, bool wake_all);
  49
  50#ifdef CONFIG_FS_DAX
  51struct page *read_dax_sector(struct block_device *bdev, sector_t n);
  52int __dax_zero_page_range(struct block_device *bdev, sector_t sector,
  53                unsigned int offset, unsigned int length);
  54#else
  55static inline struct page *read_dax_sector(struct block_device *bdev,
  56                sector_t n)
  57{
  58        return ERR_PTR(-ENXIO);
  59}
  60static 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}
  65#endif
  66
  67#ifdef CONFIG_FS_DAX_PMD
  68static 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}
  74int 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
  77static inline unsigned int dax_radix_order(void *entry)
  78{
  79        return 0;
  80}
  81static 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
  88int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
  89
  90static 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}
  94
  95static inline bool dax_mapping(struct address_space *mapping)
  96{
  97        return mapping->host && IS_DAX(mapping->host);
  98}
  99
 100struct writeback_control;
 101int dax_writeback_mapping_range(struct address_space *mapping,
 102                struct block_device *bdev, struct writeback_control *wbc);
 103#endif
 104