lib: zstd: Add kernel-specific API

This patch:
- Moves `include/linux/zstd.h` -> `include/linux/zstd_lib.h`
- Updates modified zstd headers to yearless copyright
- Adds a new API in `include/linux/zstd.h` that is functionally
  equivalent to the in-use subset of the current API. Functions are
  renamed to avoid symbol collisions with zstd, to make it clear it is
  not the upstream zstd API, and to follow the kernel style guide.
- Updates all callers to use the new API.

There are no functional changes in this patch. Since there are no
functional change, I felt it was okay to update all the callers in a
single patch. Once the API is approved, the callers are mechanically
changed.

This patch is preparing for the 3rd patch in this series, which updates
zstd to version 1.4.10. Since the upstream zstd API is no longer exposed
to callers, the update can happen transparently.

Signed-off-by: Nick Terrell <terrelln@fb.com>
Tested By: Paul Jones <paul@pauljones.id.au>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 on x86-64
Tested-by: Jean-Denis Girard <jd.girard@sysnux.pf>

3 files changed, 185 insertions, 92 deletions

diff --git a/lib/decompress_unzstd.c b/lib/decompress_unzstd.c
index 6b629ab31c1e..c076d6f05064 100644
--- a/lib/decompress_unzstd.c
+++ b/lib/decompress_unzstd.c
@@ -91,11 +91,15 @@
 
 static int INIT handle_zstd_error(size_t ret, void (*error)(char *x))
 {
-	const int err = ZSTD_getErrorCode(ret);
+	const zstd_error_code err = zstd_get_error_code(ret);
 
-	if (!ZSTD_isError(ret))
+	if (!zstd_is_error(ret))
 		return 0;
 
+	/*
+	 * zstd_get_error_name() cannot be used because error takes a char *
+	 * not a const char *
+	 */
 	switch (err) {
 	case ZSTD_error_memory_allocation:
 		error("ZSTD decompressor ran out of memory");
@@ -124,28 +128,28 @@ static int INIT decompress_single(const u8 *in_buf, long in_len, u8 *out_buf,
 				  long out_len, long *in_pos,
 				  void (*error)(char *x))
 {
-	const size_t wksp_size = ZSTD_DCtxWorkspaceBound();
+	const size_t wksp_size = zstd_dctx_workspace_bound();
 	void *wksp = large_malloc(wksp_size);
-	ZSTD_DCtx *dctx = ZSTD_initDCtx(wksp, wksp_size);
+	zstd_dctx *dctx = zstd_init_dctx(wksp, wksp_size);
 	int err;
 	size_t ret;
 
 	if (dctx == NULL) {
-		error("Out of memory while allocating ZSTD_DCtx");
+		error("Out of memory while allocating zstd_dctx");
 		err = -1;
 		goto out;
 	}
 	/*
 	 * Find out how large the frame actually is, there may be junk at
-	 * the end of the frame that ZSTD_decompressDCtx() can't handle.
+	 * the end of the frame that zstd_decompress_dctx() can't handle.
 	 */
-	ret = ZSTD_findFrameCompressedSize(in_buf, in_len);
+	ret = zstd_find_frame_compressed_size(in_buf, in_len);
 	err = handle_zstd_error(ret, error);
 	if (err)
 		goto out;
 	in_len = (long)ret;
 
-	ret = ZSTD_decompressDCtx(dctx, out_buf, out_len, in_buf, in_len);
+	ret = zstd_decompress_dctx(dctx, out_buf, out_len, in_buf, in_len);
 	err = handle_zstd_error(ret, error);
 	if (err)
 		goto out;
@@ -167,14 +171,14 @@ static int INIT __unzstd(unsigned char *in_buf, long in_len,
 			 long *in_pos,
 			 void (*error)(char *x))
 {
-	ZSTD_inBuffer in;
-	ZSTD_outBuffer out;
-	ZSTD_frameParams params;
+	zstd_in_buffer in;
+	zstd_out_buffer out;
+	zstd_frame_header header;
 	void *in_allocated = NULL;
 	void *out_allocated = NULL;
 	void *wksp = NULL;
 	size_t wksp_size;
-	ZSTD_DStream *dstream;
+	zstd_dstream *dstream;
 	int err;
 	size_t ret;
 
@@ -238,13 +242,13 @@ static int INIT __unzstd(unsigned char *in_buf, long in_len,
 	out.size = out_len;
 
 	/*
-	 * We need to know the window size to allocate the ZSTD_DStream.
+	 * We need to know the window size to allocate the zstd_dstream.
 	 * Since we are streaming, we need to allocate a buffer for the sliding
 	 * window. The window size varies from 1 KB to ZSTD_WINDOWSIZE_MAX
 	 * (8 MB), so it is important to use the actual value so as not to
 	 * waste memory when it is smaller.
 	 */
-	ret = ZSTD_getFrameParams(&params, in.src, in.size);
+	ret = zstd_get_frame_header(&header, in.src, in.size);
 	err = handle_zstd_error(ret, error);
 	if (err)
 		goto out;
@@ -253,19 +257,19 @@ static int INIT __unzstd(unsigned char *in_buf, long in_len,
 		err = -1;
 		goto out;
 	}
-	if (params.windowSize > ZSTD_WINDOWSIZE_MAX) {
+	if (header.windowSize > ZSTD_WINDOWSIZE_MAX) {
 		error("ZSTD-compressed data has too large a window size");
 		err = -1;
 		goto out;
 	}
 
 	/*
-	 * Allocate the ZSTD_DStream now that we know how much memory is
+	 * Allocate the zstd_dstream now that we know how much memory is
 	 * required.
 	 */
-	wksp_size = ZSTD_DStreamWorkspaceBound(params.windowSize);
+	wksp_size = zstd_dstream_workspace_bound(header.windowSize);
 	wksp = large_malloc(wksp_size);
-	dstream = ZSTD_initDStream(params.windowSize, wksp, wksp_size);
+	dstream = zstd_init_dstream(header.windowSize, wksp, wksp_size);
 	if (dstream == NULL) {
 		error("Out of memory while allocating ZSTD_DStream");
 		err = -1;
@@ -298,7 +302,7 @@ static int INIT __unzstd(unsigned char *in_buf, long in_len,
 			in.size = in_len;
 		}
 		/* Returns zero when the frame is complete. */
-		ret = ZSTD_decompressStream(dstream, &out, &in);
+		ret = zstd_decompress_stream(dstream, &out, &in);
 		err = handle_zstd_error(ret, error);
 		if (err)
 			goto out;
diff --git a/lib/zstd/compress.c b/lib/zstd/compress.c
index b080264ed3ad..57aaa64306a0 100644
--- a/lib/zstd/compress.c
+++ b/lib/zstd/compress.c
@@ -3443,43 +3443,92 @@ ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long srcSize,
 	return params;
 }
 
-EXPORT_SYMBOL(ZSTD_maxCLevel);
-EXPORT_SYMBOL(ZSTD_compressBound);
-
-EXPORT_SYMBOL(ZSTD_CCtxWorkspaceBound);
-EXPORT_SYMBOL(ZSTD_initCCtx);
-EXPORT_SYMBOL(ZSTD_compressCCtx);
-EXPORT_SYMBOL(ZSTD_compress_usingDict);
-
-EXPORT_SYMBOL(ZSTD_CDictWorkspaceBound);
-EXPORT_SYMBOL(ZSTD_initCDict);
-EXPORT_SYMBOL(ZSTD_compress_usingCDict);
-
-EXPORT_SYMBOL(ZSTD_CStreamWorkspaceBound);
-EXPORT_SYMBOL(ZSTD_initCStream);
-EXPORT_SYMBOL(ZSTD_initCStream_usingCDict);
-EXPORT_SYMBOL(ZSTD_resetCStream);
-EXPORT_SYMBOL(ZSTD_compressStream);
-EXPORT_SYMBOL(ZSTD_flushStream);
-EXPORT_SYMBOL(ZSTD_endStream);
-EXPORT_SYMBOL(ZSTD_CStreamInSize);
-EXPORT_SYMBOL(ZSTD_CStreamOutSize);
-
-EXPORT_SYMBOL(ZSTD_getCParams);
-EXPORT_SYMBOL(ZSTD_getParams);
-EXPORT_SYMBOL(ZSTD_checkCParams);
-EXPORT_SYMBOL(ZSTD_adjustCParams);
-
-EXPORT_SYMBOL(ZSTD_compressBegin);
-EXPORT_SYMBOL(ZSTD_compressBegin_usingDict);
-EXPORT_SYMBOL(ZSTD_compressBegin_advanced);
-EXPORT_SYMBOL(ZSTD_copyCCtx);
-EXPORT_SYMBOL(ZSTD_compressBegin_usingCDict);
-EXPORT_SYMBOL(ZSTD_compressContinue);
-EXPORT_SYMBOL(ZSTD_compressEnd);
-
-EXPORT_SYMBOL(ZSTD_getBlockSizeMax);
-EXPORT_SYMBOL(ZSTD_compressBlock);
+size_t zstd_compress_bound(size_t src_size)
+{
+	return ZSTD_compressBound(src_size);
+}
+EXPORT_SYMBOL(zstd_compress_bound);
+
+int zstd_min_clevel(void)
+{
+	/*
+	 * zstd-1.3.1 doesn't implement ZSTD_minCLevel().
+	 * Return 0 (default level).
+	 */
+	return 0;
+}
+EXPORT_SYMBOL(zstd_min_clevel);
+
+int zstd_max_clevel(void)
+{
+	return ZSTD_maxCLevel();
+}
+EXPORT_SYMBOL(zstd_max_clevel);
+
+zstd_parameters zstd_get_params(int level,
+	unsigned long long estimated_src_size)
+{
+	return ZSTD_getParams(level, estimated_src_size, 0);
+}
+EXPORT_SYMBOL(zstd_get_params);
+
+size_t zstd_cctx_workspace_bound(const zstd_compression_parameters *cparams)
+{
+	return ZSTD_CCtxWorkspaceBound(*cparams);
+}
+EXPORT_SYMBOL(zstd_cctx_workspace_bound);
+
+zstd_cctx *zstd_init_cctx(void *workspace, size_t workspace_size)
+{
+	return ZSTD_initCCtx(workspace, workspace_size);
+}
+EXPORT_SYMBOL(zstd_init_cctx);
+
+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)
+{
+	return ZSTD_compressCCtx(cctx, dst, dst_capacity, src, src_size, *parameters);
+}
+EXPORT_SYMBOL(zstd_compress_cctx);
+
+size_t zstd_cstream_workspace_bound(const zstd_compression_parameters *cparams)
+{
+	return ZSTD_CStreamWorkspaceBound(*cparams);
+}
+EXPORT_SYMBOL(zstd_cstream_workspace_bound);
+
+zstd_cstream *zstd_init_cstream(const zstd_parameters *parameters,
+	unsigned long long pledged_src_size, void *workspace, size_t workspace_size)
+{
+	return ZSTD_initCStream(*parameters, pledged_src_size, workspace, workspace_size);
+}
+EXPORT_SYMBOL(zstd_init_cstream);
+
+size_t zstd_reset_cstream(zstd_cstream *cstream,
+	unsigned long long pledged_src_size)
+{
+	return ZSTD_resetCStream(cstream, pledged_src_size);
+}
+EXPORT_SYMBOL(zstd_reset_cstream);
+
+size_t zstd_compress_stream(zstd_cstream *cstream, zstd_out_buffer *output,
+	zstd_in_buffer *input)
+{
+	return ZSTD_compressStream(cstream, output, input);
+}
+EXPORT_SYMBOL(zstd_compress_stream);
+
+size_t zstd_flush_stream(zstd_cstream *cstream, zstd_out_buffer *output)
+{
+	return ZSTD_flushStream(cstream, output);
+}
+EXPORT_SYMBOL(zstd_flush_stream);
+
+size_t zstd_end_stream(zstd_cstream *cstream, zstd_out_buffer *output)
+{
+	return ZSTD_endStream(cstream, output);
+}
+EXPORT_SYMBOL(zstd_end_stream);
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_DESCRIPTION("Zstd Compressor");
diff --git a/lib/zstd/decompress.c b/lib/zstd/decompress.c
index 66cd487a326a..02e92c2cbf4f 100644
--- a/lib/zstd/decompress.c
+++ b/lib/zstd/decompress.c
@@ -2490,42 +2490,82 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inB
 	}
 }
 
-EXPORT_SYMBOL(ZSTD_DCtxWorkspaceBound);
-EXPORT_SYMBOL(ZSTD_initDCtx);
-EXPORT_SYMBOL(ZSTD_decompressDCtx);
-EXPORT_SYMBOL(ZSTD_decompress_usingDict);
-
-EXPORT_SYMBOL(ZSTD_DDictWorkspaceBound);
-EXPORT_SYMBOL(ZSTD_initDDict);
-EXPORT_SYMBOL(ZSTD_decompress_usingDDict);
-
-EXPORT_SYMBOL(ZSTD_DStreamWorkspaceBound);
-EXPORT_SYMBOL(ZSTD_initDStream);
-EXPORT_SYMBOL(ZSTD_initDStream_usingDDict);
-EXPORT_SYMBOL(ZSTD_resetDStream);
-EXPORT_SYMBOL(ZSTD_decompressStream);
-EXPORT_SYMBOL(ZSTD_DStreamInSize);
-EXPORT_SYMBOL(ZSTD_DStreamOutSize);
-
-EXPORT_SYMBOL(ZSTD_findFrameCompressedSize);
-EXPORT_SYMBOL(ZSTD_getFrameContentSize);
-EXPORT_SYMBOL(ZSTD_findDecompressedSize);
-
-EXPORT_SYMBOL(ZSTD_isFrame);
-EXPORT_SYMBOL(ZSTD_getDictID_fromDict);
-EXPORT_SYMBOL(ZSTD_getDictID_fromDDict);
-EXPORT_SYMBOL(ZSTD_getDictID_fromFrame);
-
-EXPORT_SYMBOL(ZSTD_getFrameParams);
-EXPORT_SYMBOL(ZSTD_decompressBegin);
-EXPORT_SYMBOL(ZSTD_decompressBegin_usingDict);
-EXPORT_SYMBOL(ZSTD_copyDCtx);
-EXPORT_SYMBOL(ZSTD_nextSrcSizeToDecompress);
-EXPORT_SYMBOL(ZSTD_decompressContinue);
-EXPORT_SYMBOL(ZSTD_nextInputType);
-
-EXPORT_SYMBOL(ZSTD_decompressBlock);
-EXPORT_SYMBOL(ZSTD_insertBlock);
+unsigned int zstd_is_error(size_t code)
+{
+	return ZSTD_isError(code);
+}
+EXPORT_SYMBOL(zstd_is_error);
+
+zstd_error_code zstd_get_error_code(size_t code)
+{
+	return ZSTD_getErrorCode(code);
+}
+EXPORT_SYMBOL(zstd_get_error_code);
+
+const char *zstd_get_error_name(size_t code)
+{
+	/* Real implementation in zstd-1.4.6. */
+	return "GENERIC";
+}
+EXPORT_SYMBOL(zstd_get_error_name);
+
+size_t zstd_dctx_workspace_bound(void)
+{
+	return ZSTD_DCtxWorkspaceBound();
+}
+EXPORT_SYMBOL(zstd_dctx_workspace_bound);
+
+zstd_dctx *zstd_init_dctx(void *workspace, size_t workspace_size)
+{
+	return ZSTD_initDCtx(workspace, workspace_size);
+}
+EXPORT_SYMBOL(zstd_init_dctx);
+
+size_t zstd_decompress_dctx(zstd_dctx *dctx, void *dst, size_t dst_capacity,
+	const void *src, size_t src_size)
+{
+	return ZSTD_decompressDCtx(dctx, dst, dst_capacity, src, src_size);
+}
+EXPORT_SYMBOL(zstd_decompress_dctx);
+
+size_t zstd_dstream_workspace_bound(size_t max_window_size)
+{
+	return ZSTD_DStreamWorkspaceBound(max_window_size);
+}
+EXPORT_SYMBOL(zstd_dstream_workspace_bound);
+
+zstd_dstream *zstd_init_dstream(size_t max_window_size, void *workspace,
+	size_t workspace_size)
+{
+	return ZSTD_initDStream(max_window_size, workspace, workspace_size);
+}
+EXPORT_SYMBOL(zstd_init_dstream);
+
+size_t zstd_reset_dstream(zstd_dstream *dstream)
+{
+	return ZSTD_resetDStream(dstream);
+}
+EXPORT_SYMBOL(zstd_reset_dstream);
+
+size_t zstd_decompress_stream(zstd_dstream *dstream, zstd_out_buffer *output,
+	zstd_in_buffer *input)
+{
+	return ZSTD_decompressStream(dstream, output, input);
+}
+EXPORT_SYMBOL(zstd_decompress_stream);
+
+size_t zstd_find_frame_compressed_size(const void *src, size_t src_size)
+{
+	return ZSTD_findFrameCompressedSize(src, src_size);
+}
+EXPORT_SYMBOL(zstd_find_frame_compressed_size);
+
+size_t zstd_get_frame_header(zstd_frame_header *header, const void *src,
+	size_t src_size)
+{
+	return ZSTD_getFrameParams(header, src, src_size);
+}
+EXPORT_SYMBOL(zstd_get_frame_header);
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_DESCRIPTION("Zstd Decompressor");