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 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 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 } 38 39 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 40 struct iomap_ops *ops); 41 int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, 42 struct iomap_ops *ops); 43 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); 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); 47 void dax_wake_mapping_entry_waiter(struct address_space *mapping, 48 pgoff_t index, void *entry, bool wake_all); 49 50 #ifdef CONFIG_FS_DAX 51 struct page *read_dax_sector(struct block_device *bdev, sector_t n); 52 int __dax_zero_page_range(struct block_device *bdev, sector_t sector, 53 unsigned int offset, unsigned int length); 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 } 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 } 65 #endif 66 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 88 int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *); 89 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 } 94 95 static inline bool dax_mapping(struct address_space *mapping) 96 { 97 return mapping->host && IS_DAX(mapping->host); 98 } 99 100 struct writeback_control; 101 int dax_writeback_mapping_range(struct address_space *mapping, 102 struct block_device *bdev, struct writeback_control *wbc); 103 #endif 104