drivers/block/zram/zcomp.h

   1 /*
   2  * Copyright (C) 2014 Sergey Senozhatsky.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9
  10 #ifndef _ZCOMP_H_
  11 #define _ZCOMP_H_
  12
  13 #include <linux/mutex.h>
  14
  15 struct zcomp_strm {
  16         /* compression/decompression buffer */
  17         void *buffer;
  18         /*
  19          * The private data of the compression stream, only compression
  20          * stream backend can touch this (e.g. compression algorithm
  21          * working memory)
  22          */
  23         void *private;
  24         /* used in multi stream backend, protected by backend strm_lock */
  25         struct list_head list;
  26 };
  27
  28 /* static compression backend */
  29 struct zcomp_backend {
  30         int (*compress)(const unsigned char *src, unsigned char *dst,
  31                         size_t *dst_len, void *private);
  32
  33         int (*decompress)(const unsigned char *src, size_t src_len,
  34                         unsigned char *dst);
  35
  36         void *(*create)(void);
  37         void (*destroy)(void *private);
  38
  39         const char *name;
  40 };
  41
  42 /* dynamic per-device compression frontend */
  43 struct zcomp {
  44         void *stream;
  45         struct zcomp_backend *backend;
  46
  47         struct zcomp_strm *(*strm_find)(struct zcomp *comp);
  48         void (*strm_release)(struct zcomp *comp, struct zcomp_strm *zstrm);
  49         bool (*set_max_streams)(struct zcomp *comp, int num_strm);
  50         void (*destroy)(struct zcomp *comp);
  51 };
  52
  53 ssize_t zcomp_available_show(const char *comp, char *buf);
  54
  55 struct zcomp *zcomp_create(const char *comp, int max_strm);
  56 void zcomp_destroy(struct zcomp *comp);
  57
  58 struct zcomp_strm *zcomp_strm_find(struct zcomp *comp);
  59 void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm);
  60
  61 int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
  62                 const unsigned char *src, size_t *dst_len);
  63
  64 int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
  65                 size_t src_len, unsigned char *dst);
  66
  67 bool zcomp_set_max_streams(struct zcomp *comp, int num_strm);
  68 #endif /* _ZCOMP_H_ */