lib: zstd: export API needed for dictionary support

Patch series "zram: introduce custom comp backends API", v7.

This series introduces support for run-time compression algorithms tuning,
so users, for instance, can adjust compression/acceleration levels and
provide pre-trained compression/decompression dictionaries which certain
algorithms support.

At this point we stop supporting (old/deprecated) comp API.  We may add
new acomp API support in the future, but before that zram needs to undergo
some major rework (we are not ready for async compression).

Some benchmarks for reference (look at column #2)

*** init zstd
/sys/block/zram0/mm_stat
1750659072 504622188 514355200        0 514355200        1        0    34204    34204

*** init zstd dict=/home/ss/zstd-dict-amd64
/sys/block/zram0/mm_stat
1750650880 465908890 475398144        0 475398144        1        0    34185    34185

*** init zstd level=8 dict=/home/ss/zstd-dict-amd64
/sys/block/zram0/mm_stat
1750654976 430803319 439873536        0 439873536        1        0    34185    34185

*** init lz4
/sys/block/zram0/mm_stat
1750646784 664266564 677060608        0 677060608        1        0    34288    34288

*** init lz4 dict=/home/ss/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750650880 619990300 632102912        0 632102912        1        0    34278    34278

*** init lz4hc
/sys/block/zram0/mm_stat
1750630400 609023822 621232128        0 621232128        1        0    34288    34288

*** init lz4hc dict=/home/ss/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750659072 505133172 515231744        0 515231744        1        0    34278    34278


Recompress
init zram zstd (prio=0), zstd level=5 (prio 1), zstd with dict (prio 2)

*** zstd
/sys/block/zram0/mm_stat
1750982656 504630584 514269184        0 514269184        1        0    34204    34204

*** idle recompress priority=1 (zstd level=5)
/sys/block/zram0/mm_stat
1750982656 488645601 525438976        0 514269184        1        0    34204    34204

*** idle recompress priority=2 (zstd dict)
/sys/block/zram0/mm_stat
1750982656 460869640 517914624        0 514269184        1        0    34185    34204


This patch (of 24):

We need to export a number of API functions that enable advanced zstd
usage - C/D dictionaries, dictionaries sharing between contexts, etc.

Link: https://lkml.kernel.org/r/20240902105656.1383858-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20240902105656.1383858-2-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 85 insertions, 0 deletions

diff --git a/lib/zstd/zstd_compress_module.c b/lib/zstd/zstd_compress_module.c
index 04e1b5c01d9b..bd8784449b31 100644
--- a/lib/zstd/zstd_compress_module.c
+++ b/lib/zstd/zstd_compress_module.c
@@ -66,6 +66,12 @@ int zstd_max_clevel(void)
 }
 EXPORT_SYMBOL(zstd_max_clevel);
 
+int zstd_default_clevel(void)
+{
+	return ZSTD_defaultCLevel();
+}
+EXPORT_SYMBOL(zstd_default_clevel);
+
 size_t zstd_compress_bound(size_t src_size)
 {
 	return ZSTD_compressBound(src_size);
@@ -79,6 +85,13 @@ zstd_parameters zstd_get_params(int level,
 }
 EXPORT_SYMBOL(zstd_get_params);
 
+zstd_compression_parameters zstd_get_cparams(int level,
+	unsigned long long estimated_src_size, size_t dict_size)
+{
+	return ZSTD_getCParams(level, estimated_src_size, dict_size);
+}
+EXPORT_SYMBOL(zstd_get_cparams);
+
 size_t zstd_cctx_workspace_bound(const zstd_compression_parameters *cparams)
 {
 	return ZSTD_estimateCCtxSize_usingCParams(*cparams);
@@ -93,6 +106,33 @@ zstd_cctx *zstd_init_cctx(void *workspace, size_t workspace_size)
 }
 EXPORT_SYMBOL(zstd_init_cctx);
 
+zstd_cctx *zstd_create_cctx_advanced(zstd_custom_mem custom_mem)
+{
+	return ZSTD_createCCtx_advanced(custom_mem);
+}
+EXPORT_SYMBOL(zstd_create_cctx_advanced);
+
+size_t zstd_free_cctx(zstd_cctx *cctx)
+{
+	return ZSTD_freeCCtx(cctx);
+}
+EXPORT_SYMBOL(zstd_free_cctx);
+
+zstd_cdict *zstd_create_cdict_byreference(const void *dict, size_t dict_size,
+					  zstd_compression_parameters cparams,
+					  zstd_custom_mem custom_mem)
+{
+	return ZSTD_createCDict_advanced(dict, dict_size, ZSTD_dlm_byRef,
+					 ZSTD_dct_auto, cparams, custom_mem);
+}
+EXPORT_SYMBOL(zstd_create_cdict_byreference);
+
+size_t zstd_free_cdict(zstd_cdict *cdict)
+{
+	return ZSTD_freeCDict(cdict);
+}
+EXPORT_SYMBOL(zstd_free_cdict);
+
 size_t zstd_compress_cctx(zstd_cctx *cctx, void *dst, size_t dst_capacity,
 	const void *src, size_t src_size, const zstd_parameters *parameters)
 {
@@ -101,6 +141,15 @@ size_t zstd_compress_cctx(zstd_cctx *cctx, void *dst, size_t dst_capacity,
 }
 EXPORT_SYMBOL(zstd_compress_cctx);
 
+size_t zstd_compress_using_cdict(zstd_cctx *cctx, void *dst,
+	size_t dst_capacity, const void *src, size_t src_size,
+	const ZSTD_CDict *cdict)
+{
+	return ZSTD_compress_usingCDict(cctx, dst, dst_capacity,
+					src, src_size, cdict);
+}
+EXPORT_SYMBOL(zstd_compress_using_cdict);
+
 size_t zstd_cstream_workspace_bound(const zstd_compression_parameters *cparams)
 {
 	return ZSTD_estimateCStreamSize_usingCParams(*cparams);
diff --git a/lib/zstd/zstd_decompress_module.c b/lib/zstd/zstd_decompress_module.c
index f4ed952ed485..469fc3059be0 100644
--- a/lib/zstd/zstd_decompress_module.c
+++ b/lib/zstd/zstd_decompress_module.c
@@ -44,6 +44,33 @@ size_t zstd_dctx_workspace_bound(void)
 }
 EXPORT_SYMBOL(zstd_dctx_workspace_bound);
 
+zstd_dctx *zstd_create_dctx_advanced(zstd_custom_mem custom_mem)
+{
+	return ZSTD_createDCtx_advanced(custom_mem);
+}
+EXPORT_SYMBOL(zstd_create_dctx_advanced);
+
+size_t zstd_free_dctx(zstd_dctx *dctx)
+{
+	return ZSTD_freeDCtx(dctx);
+}
+EXPORT_SYMBOL(zstd_free_dctx);
+
+zstd_ddict *zstd_create_ddict_byreference(const void *dict, size_t dict_size,
+					  zstd_custom_mem custom_mem)
+{
+	return ZSTD_createDDict_advanced(dict, dict_size, ZSTD_dlm_byRef,
+					 ZSTD_dct_auto, custom_mem);
+
+}
+EXPORT_SYMBOL(zstd_create_ddict_byreference);
+
+size_t zstd_free_ddict(zstd_ddict *ddict)
+{
+	return ZSTD_freeDDict(ddict);
+}
+EXPORT_SYMBOL(zstd_free_ddict);
+
 zstd_dctx *zstd_init_dctx(void *workspace, size_t workspace_size)
 {
 	if (workspace == NULL)
@@ -59,6 +86,15 @@ size_t zstd_decompress_dctx(zstd_dctx *dctx, void *dst, size_t dst_capacity,
 }
 EXPORT_SYMBOL(zstd_decompress_dctx);
 
+size_t zstd_decompress_using_ddict(zstd_dctx *dctx,
+	void *dst, size_t dst_capacity, const void* src, size_t src_size,
+	const zstd_ddict* ddict)
+{
+	return ZSTD_decompress_usingDDict(dctx, dst, dst_capacity, src,
+					  src_size, ddict);
+}
+EXPORT_SYMBOL(zstd_decompress_using_ddict);
+
 size_t zstd_dstream_workspace_bound(size_t max_window_size)
 {
 	return ZSTD_estimateDStreamSize(max_window_size);