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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * Copyright (C) 2019 HUAWEI, Inc.4 * https://www.huawei.com/5 */6#ifndef __EROFS_FS_COMPRESS_H7#define __EROFS_FS_COMPRESS_H8 9#include "internal.h"10 11struct z_erofs_decompress_req {12 struct super_block *sb;13 struct page **in, **out;14 unsigned short pageofs_in, pageofs_out;15 unsigned int inputsize, outputsize;16 17 unsigned int alg; /* the algorithm for decompression */18 bool inplace_io, partial_decoding, fillgaps;19 gfp_t gfp; /* allocation flags for extra temporary buffers */20};21 22struct z_erofs_decompressor {23 int (*config)(struct super_block *sb, struct erofs_super_block *dsb,24 void *data, int size);25 int (*decompress)(struct z_erofs_decompress_req *rq,26 struct page **pagepool);27 int (*init)(void);28 void (*exit)(void);29 char *name;30};31 32/* some special page->private (unsigned long, see below) */33#define Z_EROFS_SHORTLIVED_PAGE (-1UL << 2)34#define Z_EROFS_PREALLOCATED_PAGE (-2UL << 2)35 36/*37 * For all pages in a pcluster, page->private should be one of38 * Type Last 2bits page->private39 * short-lived page 00 Z_EROFS_SHORTLIVED_PAGE40 * preallocated page (tryalloc) 00 Z_EROFS_PREALLOCATED_PAGE41 * cached/managed page 00 pointer to z_erofs_pcluster42 * online page (file-backed, 01/10/11 sub-index << 2 | count43 * some pages can be used for inplace I/O)44 *45 * page->mapping should be one of46 * Type page->mapping47 * short-lived page NULL48 * preallocated page NULL49 * cached/managed page non-NULL or NULL (invalidated/truncated page)50 * online page non-NULL51 *52 * For all managed pages, PG_private should be set with 1 extra refcount,53 * which is used for page reclaim / migration.54 */55 56/*57 * Currently, short-lived pages are pages directly from buddy system58 * with specific page->private (Z_EROFS_SHORTLIVED_PAGE).59 * In the future world of Memdescs, it should be type 0 (Misc) memory60 * which type can be checked with a new helper.61 */62static inline bool z_erofs_is_shortlived_page(struct page *page)63{64 return page->private == Z_EROFS_SHORTLIVED_PAGE;65}66 67static inline bool z_erofs_put_shortlivedpage(struct page **pagepool,68 struct page *page)69{70 if (!z_erofs_is_shortlived_page(page))71 return false;72 erofs_pagepool_add(pagepool, page);73 return true;74}75 76extern const struct z_erofs_decompressor z_erofs_lzma_decomp;77extern const struct z_erofs_decompressor z_erofs_deflate_decomp;78extern const struct z_erofs_decompressor z_erofs_zstd_decomp;79extern const struct z_erofs_decompressor *z_erofs_decomp[];80 81struct z_erofs_stream_dctx {82 struct z_erofs_decompress_req *rq;83 unsigned int inpages, outpages; /* # of {en,de}coded pages */84 int no, ni; /* the current {en,de}coded page # */85 86 unsigned int avail_out; /* remaining bytes in the decoded buffer */87 unsigned int inbuf_pos, inbuf_sz;88 /* current status of the encoded buffer */89 u8 *kin, *kout; /* buffer mapped pointers */90 void *bounce; /* bounce buffer for inplace I/Os */91 bool bounced; /* is the bounce buffer used now? */92};93 94int z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx, void **dst,95 void **src, struct page **pgpl);96int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,97 unsigned int padbufsize);98int __init z_erofs_init_decompressor(void);99void z_erofs_exit_decompressor(void);100#endif101