drivers/block/zram/zcomp.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2
   3 #ifndef _ZCOMP_H_
   4 #define _ZCOMP_H_
   5
   6 #include <linux/local_lock.h>
   7
   8 #define ZCOMP_PARAM_NO_LEVEL    INT_MIN
   9
  10 /*
  11  * Immutable driver (backend) parameters. The driver may attach private
  12  * data to it (e.g. driver representation of the dictionary, etc.).
  13  *
  14  * This data is kept per-comp and is shared among execution contexts.
  15  */
  16 struct zcomp_params {
  17         void *dict;
  18         size_t dict_sz;
  19         s32 level;
  20
  21         void *drv_data;
  22 };
  23
  24 /*
  25  * Run-time driver context - scratch buffers, etc. It is modified during
  26  * request execution (compression/decompression), cannot be shared, so
  27  * it's in per-CPU area.
  28  */
  29 struct zcomp_ctx {
  30         void *context;
  31 };
  32
  33 struct zcomp_strm {
  34         local_lock_t lock;
  35         /* compression buffer */
  36         void *buffer;
  37         struct zcomp_ctx ctx;
  38 };
  39
  40 struct zcomp_req {
  41         const unsigned char *src;
  42         const size_t src_len;
  43
  44         unsigned char *dst;
  45         size_t dst_len;
  46 };
  47
  48 struct zcomp_ops {
  49         int (*compress)(struct zcomp_params *params, struct zcomp_ctx *ctx,
  50                         struct zcomp_req *req);
  51         int (*decompress)(struct zcomp_params *params, struct zcomp_ctx *ctx,
  52                           struct zcomp_req *req);
  53
  54         int (*create_ctx)(struct zcomp_params *params, struct zcomp_ctx *ctx);
  55         void (*destroy_ctx)(struct zcomp_ctx *ctx);
  56
  57         int (*setup_params)(struct zcomp_params *params);
  58         void (*release_params)(struct zcomp_params *params);
  59
  60         const char *name;
  61 };
  62
  63 /* dynamic per-device compression frontend */
  64 struct zcomp {
  65         struct zcomp_strm __percpu *stream;
  66         const struct zcomp_ops *ops;
  67         struct zcomp_params *params;
  68         struct hlist_node node;
  69 };
  70
  71 int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node);
  72 int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node);
  73 ssize_t zcomp_available_show(const char *comp, char *buf);
  74 bool zcomp_available_algorithm(const char *comp);
  75
  76 struct zcomp *zcomp_create(const char *alg, struct zcomp_params *params);
  77 void zcomp_destroy(struct zcomp *comp);
  78
  79 struct zcomp_strm *zcomp_stream_get(struct zcomp *comp);
  80 void zcomp_stream_put(struct zcomp *comp);
  81
  82 int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
  83                    const void *src, unsigned int *dst_len);
  84 int zcomp_decompress(struct zcomp *comp, struct zcomp_strm *zstrm,
  85                      const void *src, unsigned int src_len, void *dst);
  86
  87 #endif /* _ZCOMP_H_ */