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 9 struct iomap_ops; 10 struct dax_device; 11 struct dax_operations { 12 /* 13 * direct_access: translate a device-relative 14 * logical-page-offset into an absolute physical pfn. Return the 15 * number of pages available for DAX at that pfn. 16 */ 17 long (*direct_access)(struct dax_device *, pgoff_t, long, 18 void **, pfn_t *); 19 }; 20 21 int dax_read_lock(void); 22 void dax_read_unlock(int id); 23 struct dax_device *dax_get_by_host(const char *host); 24 struct dax_device *alloc_dax(void *private, const char *host, 25 const struct dax_operations *ops); 26 void put_dax(struct dax_device *dax_dev); 27 bool dax_alive(struct dax_device *dax_dev); 28 void kill_dax(struct dax_device *dax_dev); 29 void *dax_get_private(struct dax_device *dax_dev); 30 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 31 void **kaddr, pfn_t *pfn); 32 33 /* 34 * We use lowest available bit in exceptional entry for locking, one bit for 35 * the entry size (PMD) and two more to tell us if the entry is a huge zero 36 * page (HZP) or an empty entry that is just used for locking. In total four 37 * special bits. 38 * 39 * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and 40 * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem 41 * block allocation. 42 */ 43 #define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4) 44 #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT) 45 #define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1)) 46 #define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2)) 47 #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3)) 48 49 static inline unsigned long dax_radix_sector(void *entry) 50 { 51 return (unsigned long)entry >> RADIX_DAX_SHIFT; 52 } 53 54 static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags) 55 { 56 return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags | 57 ((unsigned long)sector << RADIX_DAX_SHIFT) | 58 RADIX_DAX_ENTRY_LOCK); 59 } 60 61 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 62 const struct iomap_ops *ops); 63 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 64 const struct iomap_ops *ops); 65 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); 66 int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index); 67 int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 68 pgoff_t index); 69 void dax_wake_mapping_entry_waiter(struct address_space *mapping, 70 pgoff_t index, void *entry, bool wake_all); 71 72 #ifdef CONFIG_FS_DAX 73 int __dax_zero_page_range(struct block_device *bdev, 74 struct dax_device *dax_dev, sector_t sector, 75 unsigned int offset, unsigned int length); 76 #else 77 static inline int __dax_zero_page_range(struct block_device *bdev, 78 struct dax_device *dax_dev, sector_t sector, 79 unsigned int offset, unsigned int length) 80 { 81 return -ENXIO; 82 } 83 #endif 84 85 #ifdef CONFIG_FS_DAX_PMD 86 static inline unsigned int dax_radix_order(void *entry) 87 { 88 if ((unsigned long)entry & RADIX_DAX_PMD) 89 return PMD_SHIFT - PAGE_SHIFT; 90 return 0; 91 } 92 #else 93 static inline unsigned int dax_radix_order(void *entry) 94 { 95 return 0; 96 } 97 #endif 98 int dax_pfn_mkwrite(struct vm_fault *vmf); 99 100 static inline bool vma_is_dax(struct vm_area_struct *vma) 101 { 102 return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host); 103 } 104 105 static inline bool dax_mapping(struct address_space *mapping) 106 { 107 return mapping->host && IS_DAX(mapping->host); 108 } 109 110 struct writeback_control; 111 int dax_writeback_mapping_range(struct address_space *mapping, 112 struct block_device *bdev, struct writeback_control *wbc); 113 #endif 114