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-rw-r--r--fs/erofs/compress.h60
1 files changed, 60 insertions, 0 deletions
diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
new file mode 100644
index 000000000000..07d279fd5d67
--- /dev/null
+++ b/fs/erofs/compress.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2019 HUAWEI, Inc.
+ * http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#ifndef __EROFS_FS_COMPRESS_H
+#define __EROFS_FS_COMPRESS_H
+
+#include "internal.h"
+
+enum {
+ Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
+ Z_EROFS_COMPRESSION_RUNTIME_MAX
+};
+
+struct z_erofs_decompress_req {
+ struct super_block *sb;
+ struct page **in, **out;
+
+ unsigned short pageofs_out;
+ unsigned int inputsize, outputsize;
+
+ /* indicate the algorithm will be used for decompression */
+ unsigned int alg;
+ bool inplace_io, partial_decoding;
+};
+
+/*
+ * - 0x5A110C8D ('sallocated', Z_EROFS_MAPPING_STAGING) -
+ * used to mark temporary allocated pages from other
+ * file/cached pages and NULL mapping pages.
+ */
+#define Z_EROFS_MAPPING_STAGING ((void *)0x5A110C8D)
+
+/* check if a page is marked as staging */
+static inline bool z_erofs_page_is_staging(struct page *page)
+{
+ return page->mapping == Z_EROFS_MAPPING_STAGING;
+}
+
+static inline bool z_erofs_put_stagingpage(struct list_head *pagepool,
+ struct page *page)
+{
+ if (!z_erofs_page_is_staging(page))
+ return false;
+
+ /* staging pages should not be used by others at the same time */
+ if (page_ref_count(page) > 1)
+ put_page(page);
+ else
+ list_add(&page->lru, pagepool);
+ return true;
+}
+
+int z_erofs_decompress(struct z_erofs_decompress_req *rq,
+ struct list_head *pagepool);
+
+#endif
+