fs/erofs/compress.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2019 HUAWEI, Inc.
   4  *             http://www.huawei.com/
   5  * Created by Gao Xiang <gaoxiang25@huawei.com>
   6  */
   7 #ifndef __EROFS_FS_COMPRESS_H
   8 #define __EROFS_FS_COMPRESS_H
   9
  10 #include "internal.h"
  11
  12 enum {
  13         Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
  14         Z_EROFS_COMPRESSION_RUNTIME_MAX
  15 };
  16
  17 struct z_erofs_decompress_req {
  18         struct super_block *sb;
  19         struct page **in, **out;
  20
  21         unsigned short pageofs_out;
  22         unsigned int inputsize, outputsize;
  23
  24         /* indicate the algorithm will be used for decompression */
  25         unsigned int alg;
  26         bool inplace_io, partial_decoding;
  27 };
  28
  29 /*
  30  * - 0x5A110C8D ('sallocated', Z_EROFS_MAPPING_STAGING) -
  31  * used to mark temporary allocated pages from other
  32  * file/cached pages and NULL mapping pages.
  33  */
  34 #define Z_EROFS_MAPPING_STAGING         ((void *)0x5A110C8D)
  35
  36 /* check if a page is marked as staging */
  37 static inline bool z_erofs_page_is_staging(struct page *page)
  38 {
  39         return page->mapping == Z_EROFS_MAPPING_STAGING;
  40 }
  41
  42 static inline bool z_erofs_put_stagingpage(struct list_head *pagepool,
  43                                            struct page *page)
  44 {
  45         if (!z_erofs_page_is_staging(page))
  46                 return false;
  47
  48         /* staging pages should not be used by others at the same time */
  49         if (page_ref_count(page) > 1)
  50                 put_page(page);
  51         else
  52                 list_add(&page->lru, pagepool);
  53         return true;
  54 }
  55
  56 int z_erofs_decompress(struct z_erofs_decompress_req *rq,
  57                        struct list_head *pagepool);
  58
  59 #endif
  60