linux/fs/iomap/swapfile.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2018 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <[email protected]>
 */
#include <linux/module.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/iomap.h>
#include <linux/swap.h>

/* Swapfile activation */

struct iomap_swapfile_info { … };

/*
 * Collect physical extents for this swap file.  Physical extents reported to
 * the swap code must be trimmed to align to a page boundary.  The logical
 * offset within the file is irrelevant since the swapfile code maps logical
 * page numbers of the swap device to the physical page-aligned extents.
 */
static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi)
{ … }

static int iomap_swapfile_fail(struct iomap_swapfile_info *isi, const char *str)
{ … }

/*
 * Accumulate iomaps for this swap file.  We have to accumulate iomaps because
 * swap only cares about contiguous page-aligned physical extents and makes no
 * distinction between written and unwritten extents.
 */
static loff_t iomap_swapfile_iter(const struct iomap_iter *iter,
		struct iomap *iomap, struct iomap_swapfile_info *isi)
{ … }

/*
 * Iterate a swap file's iomaps to construct physical extents that can be
 * passed to the swapfile subsystem.
 */
int iomap_swapfile_activate(struct swap_info_struct *sis,
		struct file *swap_file, sector_t *pagespan,
		const struct iomap_ops *ops)
{ … }
EXPORT_SYMBOL_GPL(…);