drivers/block/zram/zcomp_lz4.c

   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 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/lz4.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/mm.h>
  15
  16 #include "zcomp_lz4.h"
  17
  18 static void *zcomp_lz4_create(gfp_t flags)
  19 {
  20         void *ret;
  21
  22         ret = kmalloc(LZ4_MEM_COMPRESS, flags);
  23         if (!ret)
  24                 ret = __vmalloc(LZ4_MEM_COMPRESS,
  25                                 flags | __GFP_HIGHMEM,
  26                                 PAGE_KERNEL);
  27         return ret;
  28 }
  29
  30 static void zcomp_lz4_destroy(void *private)
  31 {
  32         kvfree(private);
  33 }
  34
  35 static int zcomp_lz4_compress(const unsigned char *src, unsigned char *dst,
  36                 size_t *dst_len, void *private)
  37 {
  38         /* return  : Success if return 0 */
  39         return lz4_compress(src, PAGE_SIZE, dst, dst_len, private);
  40 }
  41
  42 static int zcomp_lz4_decompress(const unsigned char *src, size_t src_len,
  43                 unsigned char *dst)
  44 {
  45         size_t dst_len = PAGE_SIZE;
  46         /* return  : Success if return 0 */
  47         return lz4_decompress_unknownoutputsize(src, src_len, dst, &dst_len);
  48 }
  49
  50 struct zcomp_backend zcomp_lz4 = {
  51         .compress = zcomp_lz4_compress,
  52         .decompress = zcomp_lz4_decompress,
  53         .create = zcomp_lz4_create,
  54         .destroy = zcomp_lz4_destroy,
  55         .name = "lz4",
  56 };