linux/fs/erofs/decompressor.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2019 HUAWEI, Inc.
 *             https://www.huawei.com/
 * Copyright (C) 2024 Alibaba Cloud
 */
#include "compress.h"
#include <linux/lz4.h>

#ifndef LZ4_DISTANCE_MAX	/* history window size */
#define LZ4_DISTANCE_MAX …
#endif

#define LZ4_MAX_DISTANCE_PAGES …
#ifndef LZ4_DECOMPRESS_INPLACE_MARGIN
#define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize) …
#endif

struct z_erofs_lz4_decompress_ctx { … };

static int z_erofs_load_lz4_config(struct super_block *sb,
			    struct erofs_super_block *dsb, void *data, int size)
{ … }

/*
 * Fill all gaps with bounce pages if it's a sparse page list. Also check if
 * all physical pages are consecutive, which can be seen for moderate CR.
 */
static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx,
					struct page **pagepool)
{ … }

static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx,
			void *inpage, void *out, unsigned int *inputmargin,
			int *maptype, bool may_inplace)
{ … }

/*
 * Get the exact inputsize with zero_padding feature.
 *  - For LZ4, it should work if zero_padding feature is on (5.3+);
 *  - For MicroLZMA, it'd be enabled all the time.
 */
int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
			 unsigned int padbufsize)
{ … }

static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
				      u8 *dst)
{ … }

static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
				  struct page **pagepool)
{ … }

static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
				   struct page **pagepool)
{ … }

int z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx, void **dst,
			       void **src, struct page **pgpl)
{ … }

const struct z_erofs_decompressor *z_erofs_decomp[] = …;

int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb)
{ … }

int __init z_erofs_init_decompressor(void)
{ … }

void z_erofs_exit_decompressor(void)
{ … }