166 lines
4.9 KiB
C
166 lines
4.9 KiB
C
#ifndef _LINUX_DAX_H
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#define _LINUX_DAX_H
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/radix-tree.h>
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#include <asm/pgtable.h>
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struct iomap_ops;
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struct dax_device;
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struct dax_operations {
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/*
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* direct_access: translate a device-relative
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* logical-page-offset into an absolute physical pfn. Return the
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* number of pages available for DAX at that pfn.
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*/
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long (*direct_access)(struct dax_device *, pgoff_t, long,
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void **, pfn_t *);
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/* copy_from_iter: required operation for fs-dax direct-i/o */
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size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
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struct iov_iter *);
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/* flush: optional driver-specific cache management after writes */
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void (*flush)(struct dax_device *, pgoff_t, void *, size_t);
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};
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extern struct attribute_group dax_attribute_group;
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#if IS_ENABLED(CONFIG_DAX)
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struct dax_device *dax_get_by_host(const char *host);
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void put_dax(struct dax_device *dax_dev);
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#else
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static inline struct dax_device *dax_get_by_host(const char *host)
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{
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return NULL;
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}
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static inline void put_dax(struct dax_device *dax_dev)
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{
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}
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#endif
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int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
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#if IS_ENABLED(CONFIG_FS_DAX)
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int __bdev_dax_supported(struct super_block *sb, int blocksize);
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static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
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{
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return __bdev_dax_supported(sb, blocksize);
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}
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static inline struct dax_device *fs_dax_get_by_host(const char *host)
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{
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return dax_get_by_host(host);
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}
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static inline void fs_put_dax(struct dax_device *dax_dev)
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{
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put_dax(dax_dev);
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}
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#else
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static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
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{
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return -EOPNOTSUPP;
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}
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static inline struct dax_device *fs_dax_get_by_host(const char *host)
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{
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return NULL;
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}
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static inline void fs_put_dax(struct dax_device *dax_dev)
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{
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}
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#endif
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int dax_read_lock(void);
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void dax_read_unlock(int id);
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struct dax_device *alloc_dax(void *private, const char *host,
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const struct dax_operations *ops);
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bool dax_alive(struct dax_device *dax_dev);
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void kill_dax(struct dax_device *dax_dev);
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void *dax_get_private(struct dax_device *dax_dev);
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long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
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void **kaddr, pfn_t *pfn);
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size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
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size_t bytes, struct iov_iter *i);
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void dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
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size_t size);
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void dax_write_cache(struct dax_device *dax_dev, bool wc);
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/*
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* We use lowest available bit in exceptional entry for locking, one bit for
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* the entry size (PMD) and two more to tell us if the entry is a huge zero
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* page (HZP) or an empty entry that is just used for locking. In total four
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* special bits.
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*
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* If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and
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* EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
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* block allocation.
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*/
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#define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
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#define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
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#define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
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#define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
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#define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))
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static inline unsigned long dax_radix_sector(void *entry)
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{
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return (unsigned long)entry >> RADIX_DAX_SHIFT;
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}
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static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
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{
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return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags |
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((unsigned long)sector << RADIX_DAX_SHIFT) |
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RADIX_DAX_ENTRY_LOCK);
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}
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ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
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const struct iomap_ops *ops);
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int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
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const struct iomap_ops *ops);
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int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
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int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
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pgoff_t index);
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void dax_wake_mapping_entry_waiter(struct address_space *mapping,
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pgoff_t index, void *entry, bool wake_all);
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#ifdef CONFIG_FS_DAX
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int __dax_zero_page_range(struct block_device *bdev,
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struct dax_device *dax_dev, sector_t sector,
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unsigned int offset, unsigned int length);
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#else
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static inline int __dax_zero_page_range(struct block_device *bdev,
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struct dax_device *dax_dev, sector_t sector,
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unsigned int offset, unsigned int length)
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{
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return -ENXIO;
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}
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#endif
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#ifdef CONFIG_FS_DAX_PMD
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static inline unsigned int dax_radix_order(void *entry)
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{
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if ((unsigned long)entry & RADIX_DAX_PMD)
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return PMD_SHIFT - PAGE_SHIFT;
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return 0;
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}
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#else
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static inline unsigned int dax_radix_order(void *entry)
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{
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return 0;
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}
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#endif
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int dax_pfn_mkwrite(struct vm_fault *vmf);
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static inline bool dax_mapping(struct address_space *mapping)
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{
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return mapping->host && IS_DAX(mapping->host);
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}
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struct writeback_control;
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int dax_writeback_mapping_range(struct address_space *mapping,
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struct block_device *bdev, struct writeback_control *wbc);
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#endif
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