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_H 7 #define __EROFS_FS_COMPRESS_H 8 9 #include "internal.h" 10 11 struct 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 22 struct 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 of 38 * Type Last 2bits page->private 39 * short-lived page 00 Z_EROFS_SHORTLIVED_PAGE 40 * preallocated page (tryalloc) 00 Z_EROFS_PREALLOCATED_PAGE 41 * cached/managed page 00 pointer to z_erofs_pcluster 42 * online page (file-backed, 01/10/11 sub-index << 2 | count 43 * some pages can be used for inplace I/O) 44 * 45 * page->mapping should be one of 46 * Type page->mapping 47 * short-lived page NULL 48 * preallocated page NULL 49 * cached/managed page non-NULL or NULL (invalidated/truncated page) 50 * online page non-NULL 51 * 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 system 58 * with specific page->private (Z_EROFS_SHORTLIVED_PAGE). 59 * In the future world of Memdescs, it should be type 0 (Misc) memory 60 * which type can be checked with a new helper. 61 */ 62 static inline bool z_erofs_is_shortlived_page(struct page *page) 63 { 64 return page->private == Z_EROFS_SHORTLIVED_PAGE; 65 } 66 67 static 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 76 extern const struct z_erofs_decompressor z_erofs_lzma_decomp; 77 extern const struct z_erofs_decompressor z_erofs_deflate_decomp; 78 extern const struct z_erofs_decompressor z_erofs_zstd_decomp; 79 extern const struct z_erofs_decompressor *z_erofs_decomp[]; 80 81 struct 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 94 int z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx, void **dst, 95 void **src, struct page **pgpl); 96 int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf, 97 unsigned int padbufsize); 98 int __init z_erofs_init_decompressor(void); 99 void z_erofs_exit_decompressor(void); 100 #endif 101