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