1 files changed, 89 insertions, 0 deletions
diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
new file mode 100644
index 000000000000..84c8e52581f4
--- /dev/null
+++ b/fs/erofs/compress.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2019 HUAWEI, Inc.
+ *             https://www.huawei.com/
+ */
+#ifndef __EROFS_FS_COMPRESS_H
+#define __EROFS_FS_COMPRESS_H
+
+#include "internal.h"
+
+struct z_erofs_decompress_req {
+	struct super_block *sb;
+	struct page **in, **out;
+	unsigned int inpages, outpages;
+	unsigned short pageofs_in, pageofs_out;
+	unsigned int inputsize, outputsize;
+
+	unsigned int alg;       /* the algorithm for decompression */
+	bool inplace_io, partial_decoding, fillgaps;
+	gfp_t gfp;      /* allocation flags for extra temporary buffers */
+};
+
+struct z_erofs_decompressor {
+	int (*config)(struct super_block *sb, struct erofs_super_block *dsb,
+		      void *data, int size);
+	const char *(*decompress)(struct z_erofs_decompress_req *rq,
+				  struct page **pagepool);
+	int (*init)(void);
+	void (*exit)(void);
+	char *name;
+};
+
+#define Z_EROFS_SHORTLIVED_PAGE		(-1UL << 2)
+#define Z_EROFS_PREALLOCATED_FOLIO	((void *)(-2UL << 2))
+
+/*
+ * Currently, short-lived pages are pages directly from buddy system
+ * with specific page->private (Z_EROFS_SHORTLIVED_PAGE).
+ * In the future world of Memdescs, it should be type 0 (Misc) memory
+ * which type can be checked with a new helper.
+ */
+static inline bool z_erofs_is_shortlived_page(struct page *page)
+{
+	return page->private == Z_EROFS_SHORTLIVED_PAGE;
+}
+
+static inline bool z_erofs_put_shortlivedpage(struct page **pagepool,
+					      struct page *page)
+{
+	if (!z_erofs_is_shortlived_page(page))
+		return false;
+	erofs_pagepool_add(pagepool, page);
+	return true;
+}
+
+extern const struct z_erofs_decompressor z_erofs_lzma_decomp;
+extern const struct z_erofs_decompressor z_erofs_deflate_decomp;
+extern const struct z_erofs_decompressor z_erofs_zstd_decomp;
+extern const struct z_erofs_decompressor *z_erofs_decomp[];
+
+struct z_erofs_stream_dctx {
+	struct z_erofs_decompress_req *rq;
+	int no, ni;			/* the current {en,de}coded page # */
+
+	unsigned int avail_out;		/* remaining bytes in the decoded buffer */
+	unsigned int inbuf_pos, inbuf_sz;
+					/* current status of the encoded buffer */
+	u8 *kin, *kout;			/* buffer mapped pointers */
+	void *bounce;			/* bounce buffer for inplace I/Os */
+	bool bounced;			/* is the bounce buffer used now? */
+};
+
+const char *z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx,
+				void **dst, void **src, struct page **pgpl);
+const char *z_erofs_fixup_insize(struct z_erofs_decompress_req *rq,
+				 const char *padbuf, unsigned int padbufsize);
+int __init z_erofs_init_decompressor(void);
+void z_erofs_exit_decompressor(void);
+int z_erofs_crypto_decompress(struct z_erofs_decompress_req *rq,
+			      struct page **pgpl);
+int z_erofs_crypto_enable_engine(const char *name, int len);
+#ifdef CONFIG_EROFS_FS_ZIP_ACCEL
+void z_erofs_crypto_disable_all_engines(void);
+int z_erofs_crypto_show_engines(char *buf, int size, char sep);
+#else
+static inline void z_erofs_crypto_disable_all_engines(void) {}
+static inline int z_erofs_crypto_show_engines(char *buf, int size, char sep) { return 0; }
+#endif
+#endif