1 files changed, 270 insertions, 0 deletions
diff --git a/include/linux/dax.h b/include/linux/dax.h
new file mode 100644
index 000000000..ba985333e
--- /dev/null
+++ b/include/linux/dax.h
@@ -0,0 +1,270 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_DAX_H
+#define _LINUX_DAX_H
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/radix-tree.h>
+
+typedef unsigned long dax_entry_t;
+
+struct dax_device;
+struct gendisk;
+struct iomap_ops;
+struct iomap_iter;
+struct iomap;
+
+enum dax_access_mode {
+	DAX_ACCESS,
+	DAX_RECOVERY_WRITE,
+};
+
+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,
+			enum dax_access_mode, void **, pfn_t *);
+	/*
+	 * Validate whether this device is usable as an fsdax backing
+	 * device.
+	 */
+	bool (*dax_supported)(struct dax_device *, struct block_device *, int,
+			sector_t, sector_t);
+	/* zero_page_range: required operation. Zero page range   */
+	int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
+	/*
+	 * recovery_write: recover a poisoned range by DAX device driver
+	 * capable of clearing poison.
+	 */
+	size_t (*recovery_write)(struct dax_device *dax_dev, pgoff_t pgoff,
+			void *addr, size_t bytes, struct iov_iter *iter);
+};
+
+struct dax_holder_operations {
+	/*
+	 * notify_failure - notify memory failure into inner holder device
+	 * @dax_dev: the dax device which contains the holder
+	 * @offset: offset on this dax device where memory failure occurs
+	 * @len: length of this memory failure event
+	 * @flags: action flags for memory failure handler
+	 */
+	int (*notify_failure)(struct dax_device *dax_dev, u64 offset,
+			u64 len, int mf_flags);
+};
+
+#if IS_ENABLED(CONFIG_DAX)
+struct dax_device *alloc_dax(void *private, const struct dax_operations *ops);
+void *dax_holder(struct dax_device *dax_dev);
+void put_dax(struct dax_device *dax_dev);
+void kill_dax(struct dax_device *dax_dev);
+void dax_write_cache(struct dax_device *dax_dev, bool wc);
+bool dax_write_cache_enabled(struct dax_device *dax_dev);
+bool dax_synchronous(struct dax_device *dax_dev);
+void set_dax_synchronous(struct dax_device *dax_dev);
+size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
+		void *addr, size_t bytes, struct iov_iter *i);
+/*
+ * Check if given mapping is supported by the file / underlying device.
+ */
+static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
+					     struct dax_device *dax_dev)
+{
+	if (!(vma->vm_flags & VM_SYNC))
+		return true;
+	if (!IS_DAX(file_inode(vma->vm_file)))
+		return false;
+	return dax_synchronous(dax_dev);
+}
+#else
+static inline void *dax_holder(struct dax_device *dax_dev)
+{
+	return NULL;
+}
+static inline struct dax_device *alloc_dax(void *private,
+		const struct dax_operations *ops)
+{
+	/*
+	 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
+	 * NULL is an error or expected.
+	 */
+	return NULL;
+}
+static inline void put_dax(struct dax_device *dax_dev)
+{
+}
+static inline void kill_dax(struct dax_device *dax_dev)
+{
+}
+static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
+{
+}
+static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
+{
+	return false;
+}
+static inline bool dax_synchronous(struct dax_device *dax_dev)
+{
+	return true;
+}
+static inline void set_dax_synchronous(struct dax_device *dax_dev)
+{
+}
+static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
+				struct dax_device *dax_dev)
+{
+	return !(vma->vm_flags & VM_SYNC);
+}
+static inline size_t dax_recovery_write(struct dax_device *dax_dev,
+		pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
+{
+	return 0;
+}
+#endif
+
+void set_dax_nocache(struct dax_device *dax_dev);
+void set_dax_nomc(struct dax_device *dax_dev);
+
+struct writeback_control;
+#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
+int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
+void dax_remove_host(struct gendisk *disk);
+struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off,
+		void *holder, const struct dax_holder_operations *ops);
+void fs_put_dax(struct dax_device *dax_dev, void *holder);
+#else
+static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk)
+{
+	return 0;
+}
+static inline void dax_remove_host(struct gendisk *disk)
+{
+}
+static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
+		u64 *start_off, void *holder,
+		const struct dax_holder_operations *ops)
+{
+	return NULL;
+}
+static inline void fs_put_dax(struct dax_device *dax_dev, void *holder)
+{
+}
+#endif /* CONFIG_BLOCK && CONFIG_FS_DAX */
+
+#if IS_ENABLED(CONFIG_FS_DAX)
+int dax_writeback_mapping_range(struct address_space *mapping,
+		struct dax_device *dax_dev, struct writeback_control *wbc);
+
+struct page *dax_layout_busy_page(struct address_space *mapping);
+struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
+dax_entry_t dax_lock_page(struct page *page);
+void dax_unlock_page(struct page *page, dax_entry_t cookie);
+dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
+		unsigned long index, struct page **page);
+void dax_unlock_mapping_entry(struct address_space *mapping,
+		unsigned long index, dax_entry_t cookie);
+#else
+static inline struct page *dax_layout_busy_page(struct address_space *mapping)
+{
+	return NULL;
+}
+
+static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages)
+{
+	return NULL;
+}
+
+static inline int dax_writeback_mapping_range(struct address_space *mapping,
+		struct dax_device *dax_dev, struct writeback_control *wbc)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline dax_entry_t dax_lock_page(struct page *page)
+{
+	if (IS_DAX(page->mapping->host))
+		return ~0UL;
+	return 0;
+}
+
+static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
+{
+}
+
+static inline dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
+		unsigned long index, struct page **page)
+{
+	return 0;
+}
+
+static inline void dax_unlock_mapping_entry(struct address_space *mapping,
+		unsigned long index, dax_entry_t cookie)
+{
+}
+#endif
+
+int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
+		const struct iomap_ops *ops);
+int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
+		const struct iomap_ops *ops);
+
+#if IS_ENABLED(CONFIG_DAX)
+int dax_read_lock(void);
+void dax_read_unlock(int id);
+#else
+static inline int dax_read_lock(void)
+{
+	return 0;
+}
+
+static inline void dax_read_unlock(int id)
+{
+}
+#endif /* CONFIG_DAX */
+bool dax_alive(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,
+		enum dax_access_mode mode, void **kaddr, pfn_t *pfn);
+size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
+		size_t bytes, struct iov_iter *i);
+size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
+		size_t bytes, struct iov_iter *i);
+int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
+			size_t nr_pages);
+int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, u64 len,
+		int mf_flags);
+void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
+
+ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
+		const struct iomap_ops *ops);
+vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
+		    pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
+vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
+		enum page_entry_size pe_size, pfn_t pfn);
+int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
+int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
+				      pgoff_t index);
+int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
+				  struct inode *dest, loff_t destoff,
+				  loff_t len, bool *is_same,
+				  const struct iomap_ops *ops);
+int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,
+			      struct file *file_out, loff_t pos_out,
+			      loff_t *len, unsigned int remap_flags,
+			      const struct iomap_ops *ops);
+static inline bool dax_mapping(struct address_space *mapping)
+{
+	return mapping->host && IS_DAX(mapping->host);
+}
+
+#ifdef CONFIG_DEV_DAX_HMEM_DEVICES
+void hmem_register_device(int target_nid, struct resource *r);
+#else
+static inline void hmem_register_device(int target_nid, struct resource *r)
+{
+}
+#endif
+
+#endif