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kernel/linux-rt-4.4.41/drivers/block/zram/zcomp.h 1.96 KB
5113f6f70   김현기   kernel add
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  /*
   * Copyright (C) 2014 Sergey Senozhatsky.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  
  #ifndef _ZCOMP_H_
  #define _ZCOMP_H_
  
  #include <linux/mutex.h>
  
  struct zcomp_strm {
  	/* compression/decompression buffer */
  	void *buffer;
  	/*
  	 * The private data of the compression stream, only compression
  	 * stream backend can touch this (e.g. compression algorithm
  	 * working memory)
  	 */
  	void *private;
  	/* used in multi stream backend, protected by backend strm_lock */
  	struct list_head list;
  };
  
  /* static compression backend */
  struct zcomp_backend {
  	int (*compress)(const unsigned char *src, unsigned char *dst,
  			size_t *dst_len, void *private);
  
  	int (*decompress)(const unsigned char *src, size_t src_len,
  			unsigned char *dst);
  
  	void *(*create)(void);
  	void (*destroy)(void *private);
  
  	const char *name;
  };
  
  /* dynamic per-device compression frontend */
  struct zcomp {
  	void *stream;
  	struct zcomp_backend *backend;
  
  	struct zcomp_strm *(*strm_find)(struct zcomp *comp);
  	void (*strm_release)(struct zcomp *comp, struct zcomp_strm *zstrm);
  	bool (*set_max_streams)(struct zcomp *comp, int num_strm);
  	void (*destroy)(struct zcomp *comp);
  };
  
  ssize_t zcomp_available_show(const char *comp, char *buf);
  bool zcomp_available_algorithm(const char *comp);
  
  struct zcomp *zcomp_create(const char *comp, int max_strm);
  void zcomp_destroy(struct zcomp *comp);
  
  struct zcomp_strm *zcomp_strm_find(struct zcomp *comp);
  void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm);
  
  int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
  		const unsigned char *src, size_t *dst_len);
  
  int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
  		size_t src_len, unsigned char *dst);
  
  bool zcomp_set_max_streams(struct zcomp *comp, int num_strm);
  #endif /* _ZCOMP_H_ */