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 15 unsigned short pageofs_in, pageofs_out; 16 unsigned int inputsize, outputsize; 17 18 /* indicate the algorithm will be used for decompression */ 19 unsigned int alg; 20 bool inplace_io, partial_decoding, fillgaps; 21 }; 22 23 struct z_erofs_decompressor { 24 int (*config)(struct super_block *sb, struct erofs_super_block *dsb, 25 void *data, int size); 26 int (*decompress)(struct z_erofs_decompress_req *rq, 27 struct page **pagepool); 28 char *name; 29 }; 30 31 /* some special page->private (unsigned long, see below) */ 32 #define Z_EROFS_SHORTLIVED_PAGE (-1UL << 2) 33 #define Z_EROFS_PREALLOCATED_PAGE (-2UL << 2) 34 35 /* 36 * For all pages in a pcluster, page->private should be one of 37 * Type Last 2bits page->private 38 * short-lived page 00 Z_EROFS_SHORTLIVED_PAGE 39 * preallocated page (tryalloc) 00 Z_EROFS_PREALLOCATED_PAGE 40 * cached/managed page 00 pointer to z_erofs_pcluster 41 * online page (file-backed, 01/10/11 sub-index << 2 | count 42 * some pages can be used for inplace I/O) 43 * 44 * page->mapping should be one of 45 * Type page->mapping 46 * short-lived page NULL 47 * preallocated page NULL 48 * cached/managed page non-NULL or NULL (invalidated/truncated page) 49 * online page non-NULL 50 * 51 * For all managed pages, PG_private should be set with 1 extra refcount, 52 * which is used for page reclaim / migration. 53 */ 54 55 /* 56 * short-lived pages are pages directly from buddy system with specific 57 * page->private (no need to set PagePrivate since these are non-LRU / 58 * non-movable pages and bypass reclaim / migration code). 59 */ 60 static inline bool z_erofs_is_shortlived_page(struct page *page) 61 { 62 if (page->private != Z_EROFS_SHORTLIVED_PAGE) 63 return false; 64 65 DBG_BUGON(page->mapping); 66 return true; 67 } 68 69 static inline bool z_erofs_put_shortlivedpage(struct page **pagepool, 70 struct page *page) 71 { 72 if (!z_erofs_is_shortlived_page(page)) 73 return false; 74 75 /* short-lived pages should not be used by others at the same time */ 76 if (page_ref_count(page) > 1) { 77 put_page(page); 78 } else { 79 /* follow the pcluster rule above. */ 80 erofs_pagepool_add(pagepool, page); 81 } 82 return true; 83 } 84 85 #define MNGD_MAPPING(sbi) ((sbi)->managed_cache->i_mapping) 86 static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi, 87 struct page *page) 88 { 89 return page->mapping == MNGD_MAPPING(sbi); 90 } 91 92 int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf, 93 unsigned int padbufsize); 94 extern const struct z_erofs_decompressor erofs_decompressors[]; 95 96 /* prototypes for specific algorithms */ 97 int z_erofs_load_lzma_config(struct super_block *sb, 98 struct erofs_super_block *dsb, void *data, int size); 99 int z_erofs_load_deflate_config(struct super_block *sb, 100 struct erofs_super_block *dsb, void *data, int size); 101 int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq, 102 struct page **pagepool); 103 int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq, 104 struct page **pagepool); 105 #endif 106