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 #if IS_ENABLED(CONFIG_DAX) 22 struct dax_device *dax_get_by_host(const char *host); 23 void put_dax(struct dax_device *dax_dev); 24 #else 25 static inline struct dax_device *dax_get_by_host(const char *host) 26 { 27 return NULL; 28 } 29 30 static inline void put_dax(struct dax_device *dax_dev) 31 { 32 } 33 #endif 34 35 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff); 36 #if IS_ENABLED(CONFIG_FS_DAX) 37 int __bdev_dax_supported(struct super_block *sb, int blocksize); 38 static inline int bdev_dax_supported(struct super_block *sb, int blocksize) 39 { 40 return __bdev_dax_supported(sb, blocksize); 41 } 42 43 static inline struct dax_device *fs_dax_get_by_host(const char *host) 44 { 45 return dax_get_by_host(host); 46 } 47 48 static inline void fs_put_dax(struct dax_device *dax_dev) 49 { 50 put_dax(dax_dev); 51 } 52 53 #else 54 static inline int bdev_dax_supported(struct super_block *sb, int blocksize) 55 { 56 return -EOPNOTSUPP; 57 } 58 59 static inline struct dax_device *fs_dax_get_by_host(const char *host) 60 { 61 return NULL; 62 } 63 64 static inline void fs_put_dax(struct dax_device *dax_dev) 65 { 66 } 67 #endif 68 69 int dax_read_lock(void); 70 void dax_read_unlock(int id); 71 struct dax_device *alloc_dax(void *private, const char *host, 72 const struct dax_operations *ops); 73 bool dax_alive(struct dax_device *dax_dev); 74 void kill_dax(struct dax_device *dax_dev); 75 void *dax_get_private(struct dax_device *dax_dev); 76 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 77 void **kaddr, pfn_t *pfn); 78 79 /* 80 * We use lowest available bit in exceptional entry for locking, one bit for 81 * the entry size (PMD) and two more to tell us if the entry is a huge zero 82 * page (HZP) or an empty entry that is just used for locking. In total four 83 * special bits. 84 * 85 * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and 86 * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem 87 * block allocation. 88 */ 89 #define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4) 90 #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT) 91 #define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1)) 92 #define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2)) 93 #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3)) 94 95 static inline unsigned long dax_radix_sector(void *entry) 96 { 97 return (unsigned long)entry >> RADIX_DAX_SHIFT; 98 } 99 100 static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags) 101 { 102 return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags | 103 ((unsigned long)sector << RADIX_DAX_SHIFT) | 104 RADIX_DAX_ENTRY_LOCK); 105 } 106 107 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 108 const struct iomap_ops *ops); 109 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 110 const struct iomap_ops *ops); 111 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); 112 int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 113 pgoff_t index); 114 void dax_wake_mapping_entry_waiter(struct address_space *mapping, 115 pgoff_t index, void *entry, bool wake_all); 116 117 #ifdef CONFIG_FS_DAX 118 int __dax_zero_page_range(struct block_device *bdev, 119 struct dax_device *dax_dev, sector_t sector, 120 unsigned int offset, unsigned int length); 121 #else 122 static inline int __dax_zero_page_range(struct block_device *bdev, 123 struct dax_device *dax_dev, sector_t sector, 124 unsigned int offset, unsigned int length) 125 { 126 return -ENXIO; 127 } 128 #endif 129 130 #ifdef CONFIG_FS_DAX_PMD 131 static inline unsigned int dax_radix_order(void *entry) 132 { 133 if ((unsigned long)entry & RADIX_DAX_PMD) 134 return PMD_SHIFT - PAGE_SHIFT; 135 return 0; 136 } 137 #else 138 static inline unsigned int dax_radix_order(void *entry) 139 { 140 return 0; 141 } 142 #endif 143 int dax_pfn_mkwrite(struct vm_fault *vmf); 144 145 static inline bool vma_is_dax(struct vm_area_struct *vma) 146 { 147 return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host); 148 } 149 150 static inline bool dax_mapping(struct address_space *mapping) 151 { 152 return mapping->host && IS_DAX(mapping->host); 153 } 154 155 struct writeback_control; 156 int dax_writeback_mapping_range(struct address_space *mapping, 157 struct block_device *bdev, struct writeback_control *wbc); 158 #endif 159