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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2019 HUAWEI, Inc.
* https://www.huawei.com/
*/
#ifndef __EROFS_FS_COMPRESS_H
#define __EROFS_FS_COMPRESS_H
#include "internal.h"
struct z_erofs_decompress_req {
struct super_block *sb;
struct page **in, **out;
unsigned short pageofs_in, pageofs_out;
unsigned int inputsize, outputsize;
unsigned int alg; /* the algorithm for decompression */
bool inplace_io, partial_decoding, fillgaps;
gfp_t gfp; /* allocation flags for extra temporary buffers */
};
struct z_erofs_decompressor {
int (*config)(struct super_block *sb, struct erofs_super_block *dsb,
void *data, int size);
int (*decompress)(struct z_erofs_decompress_req *rq,
struct page **pagepool);
int (*init)(void);
void (*exit)(void);
char *name;
};
/* some special page->private (unsigned long, see below) */
#define Z_EROFS_SHORTLIVED_PAGE (-1UL << 2)
#define Z_EROFS_PREALLOCATED_PAGE (-2UL << 2)
/*
* For all pages in a pcluster, page->private should be one of
* Type Last 2bits page->private
* short-lived page 00 Z_EROFS_SHORTLIVED_PAGE
* preallocated page (tryalloc) 00 Z_EROFS_PREALLOCATED_PAGE
* cached/managed page 00 pointer to z_erofs_pcluster
* online page (file-backed, 01/10/11 sub-index << 2 | count
* some pages can be used for inplace I/O)
*
* page->mapping should be one of
* Type page->mapping
* short-lived page NULL
* preallocated page NULL
* cached/managed page non-NULL or NULL (invalidated/truncated page)
* online page non-NULL
*
* For all managed pages, PG_private should be set with 1 extra refcount,
* which is used for page reclaim / migration.
*/
/*
* Currently, short-lived pages are pages directly from buddy system
* with specific page->private (Z_EROFS_SHORTLIVED_PAGE).
* In the future world of Memdescs, it should be type 0 (Misc) memory
* which type can be checked with a new helper.
*/
static inline bool z_erofs_is_shortlived_page(struct page *page)
{
return page->private == Z_EROFS_SHORTLIVED_PAGE;
}
static inline bool z_erofs_put_shortlivedpage(struct page **pagepool,
struct page *page)
{
if (!z_erofs_is_shortlived_page(page))
return false;
erofs_pagepool_add(pagepool, page);
return true;
}
extern const struct z_erofs_decompressor z_erofs_lzma_decomp;
extern const struct z_erofs_decompressor z_erofs_deflate_decomp;
extern const struct z_erofs_decompressor z_erofs_zstd_decomp;
extern const struct z_erofs_decompressor *z_erofs_decomp[];
struct z_erofs_stream_dctx {
struct z_erofs_decompress_req *rq;
unsigned int inpages, outpages; /* # of {en,de}coded pages */
int no, ni; /* the current {en,de}coded page # */
unsigned int avail_out; /* remaining bytes in the decoded buffer */
unsigned int inbuf_pos, inbuf_sz;
/* current status of the encoded buffer */
u8 *kin, *kout; /* buffer mapped pointers */
void *bounce; /* bounce buffer for inplace I/Os */
bool bounced; /* is the bounce buffer used now? */
};
int z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx, void **dst,
void **src, struct page **pgpl);
int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
unsigned int padbufsize);
int __init z_erofs_init_decompressor(void);
void z_erofs_exit_decompressor(void);
#endif
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