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infra: add LZO compression

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Thomas Schoebel-Theuer 2019-07-25 08:55:17 +02:00 committed by Thomas Schoebel-Theuer
parent 3d06881801
commit a4221ada11
2 changed files with 72 additions and 0 deletions
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5
kernel/compat.h
View File

@ -230,6 +230,11 @@ extern int _compat_unlink(
#endif
/* compression stuff */
#if (defined(CONFIG_LZO_COMPRESS) || defined(CONFIG_LZO_COMPRESS_MODULE)) && \
(defined(CONFIG_LZO_DECOMPRESS) || defined(CONFIG_LZO_DECOMPRESS_MODULE))
#include <linux/lzo.h>
#define HAS_LZO
#endif
#endif /* _MARS_COMPAT */

67
kernel/mars_generic.c
View File

@ -639,6 +639,9 @@ void mref_checksum(struct mref_object *mref)
int compress_overhead = 0;
__u32 available_compression_mask =
#ifdef HAS_LZO
MREF_COMPRESS_LZO |
#endif
0;
__u32 usable_compression_mask = 0;
@ -667,6 +670,45 @@ int mars_compress(void *src_data,
goto done;
}
#ifdef HAS_LZO
if (check_flags & MREF_COMPRESS_LZO) {
int max_len = lzo1x_worst_compress(src_len);
void *wrkmem;
size_t res_len = 0;
int status;
if (!dst_data) {
tmp_buf = brick_mem_alloc(max_len);
} else if (dst_len < max_len) {
MARS_ERR("LZO compression buffer too small: %d < %d\n",
dst_len, max_len);
return 0;
}
wrkmem = brick_mem_alloc(LZO1X_1_MEM_COMPRESS);
status = lzo1x_1_compress(src_data, src_len,
tmp_buf, &res_len, wrkmem);
/* ensure that the result is really smaller */
if (status == LZO_E_OK &&
res_len > 0 &&
res_len < src_len) {
used_compression = MREF_COMPRESS_LZO;
*result_flags |= MREF_COMPRESS_LZO;
res = res_len;
/*
* TODO: avoid memcpy() by swizzling the src_data pointer
*/
if (!dst_data)
memcpy(src_data, tmp_buf, res_len);
}
brick_mem_free(wrkmem);
/* do not try other compression methods */
goto done;
}
#endif
used_compression = 0;
done:
if (!dst_data)
brick_mem_free(tmp_buf);
@ -684,6 +726,22 @@ void *mars_decompress(void *src_data,
if (!res_buf)
res_buf = brick_mem_alloc(dst_len);
#ifdef HAS_LZO
if (check_flags & MREF_COMPRESS_LZO) {
size_t res_len = dst_len;
int status;
status = lzo1x_decompress_safe(src_data, src_len,
res_buf, &res_len);
if (status == LZO_E_OK && dst_len == res_len)
goto done;
MARS_ERR("bad LZO decompression from %d to %ld bytes (requested %d)\n",
src_len, res_len, dst_len);
goto err;
}
#endif
MARS_ERR("decompression not compiled into kernel module\n");
err:
@ -749,7 +807,16 @@ int init_mars_compress(void)
{
int max_len = 0;
#ifdef HAS_LZO
max_len = lzo1x_worst_compress(MARS_MAX_COMPR_SIZE) - MARS_MAX_COMPR_SIZE;
if (max_len > compress_overhead)
compress_overhead = max_len;
#endif
#ifdef CONFIG_MARS_BENCHMARK
#ifdef HAS_LZO
benchmark_compress("lzo", MREF_COMPRESS_LZO);
#endif
(void)benchmark_compress;
#endif
return 0;