| #ifndef _LINUX_DAX_H |
| #define _LINUX_DAX_H |
| |
| #include <linux/fs.h> |
| #include <linux/mm.h> |
| #include <linux/radix-tree.h> |
| #include <asm/pgtable.h> |
| |
| struct iomap_ops; |
| struct dax_device; |
| struct dax_operations { |
| /* |
| * direct_access: translate a device-relative |
| * logical-page-offset into an absolute physical pfn. Return the |
| * number of pages available for DAX at that pfn. |
| */ |
| long (*direct_access)(struct dax_device *, pgoff_t, long, |
| void **, pfn_t *); |
| }; |
| |
| int dax_read_lock(void); |
| void dax_read_unlock(int id); |
| struct dax_device *dax_get_by_host(const char *host); |
| struct dax_device *alloc_dax(void *private, const char *host, |
| const struct dax_operations *ops); |
| void put_dax(struct dax_device *dax_dev); |
| bool dax_alive(struct dax_device *dax_dev); |
| void kill_dax(struct dax_device *dax_dev); |
| void *dax_get_private(struct dax_device *dax_dev); |
| long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, |
| void **kaddr, pfn_t *pfn); |
| |
| /* |
| * We use lowest available bit in exceptional entry for locking, one bit for |
| * the entry size (PMD) and two more to tell us if the entry is a huge zero |
| * page (HZP) or an empty entry that is just used for locking. In total four |
| * special bits. |
| * |
| * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and |
| * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem |
| * block allocation. |
| */ |
| #define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4) |
| #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT) |
| #define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1)) |
| #define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2)) |
| #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3)) |
| |
| static inline unsigned long dax_radix_sector(void *entry) |
| { |
| return (unsigned long)entry >> RADIX_DAX_SHIFT; |
| } |
| |
| static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags) |
| { |
| return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags | |
| ((unsigned long)sector << RADIX_DAX_SHIFT) | |
| RADIX_DAX_ENTRY_LOCK); |
| } |
| |
| ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, |
| const struct iomap_ops *ops); |
| int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, |
| const struct iomap_ops *ops); |
| int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); |
| int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index); |
| int dax_invalidate_mapping_entry_sync(struct address_space *mapping, |
| pgoff_t index); |
| void dax_wake_mapping_entry_waiter(struct address_space *mapping, |
| pgoff_t index, void *entry, bool wake_all); |
| |
| #ifdef CONFIG_FS_DAX |
| int __dax_zero_page_range(struct block_device *bdev, |
| struct dax_device *dax_dev, sector_t sector, |
| unsigned int offset, unsigned int length); |
| #else |
| static inline int __dax_zero_page_range(struct block_device *bdev, |
| struct dax_device *dax_dev, sector_t sector, |
| unsigned int offset, unsigned int length) |
| { |
| return -ENXIO; |
| } |
| #endif |
| |
| #ifdef CONFIG_FS_DAX_PMD |
| static inline unsigned int dax_radix_order(void *entry) |
| { |
| if ((unsigned long)entry & RADIX_DAX_PMD) |
| return PMD_SHIFT - PAGE_SHIFT; |
| return 0; |
| } |
| #else |
| static inline unsigned int dax_radix_order(void *entry) |
| { |
| return 0; |
| } |
| #endif |
| int dax_pfn_mkwrite(struct vm_fault *vmf); |
| |
| static inline bool vma_is_dax(struct vm_area_struct *vma) |
| { |
| return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host); |
| } |
| |
| static inline bool dax_mapping(struct address_space *mapping) |
| { |
| return mapping->host && IS_DAX(mapping->host); |
| } |
| |
| struct writeback_control; |
| int dax_writeback_mapping_range(struct address_space *mapping, |
| struct block_device *bdev, struct writeback_control *wbc); |
| #endif |