cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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compress.h (2944B)

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