v4.19.13 snapshot.
diff --git a/fs/squashfs/decompressor.c b/fs/squashfs/decompressor.c
new file mode 100644
index 0000000..8366398
--- /dev/null
+++ b/fs/squashfs/decompressor.c
@@ -0,0 +1,155 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * decompressor.c
+ */
+
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/buffer_head.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "decompressor.h"
+#include "squashfs.h"
+#include "page_actor.h"
+
+/*
+ * This file (and decompressor.h) implements a decompressor framework for
+ * Squashfs, allowing multiple decompressors to be easily supported
+ */
+
+static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = {
+ NULL, NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0
+};
+
+#ifndef CONFIG_SQUASHFS_LZ4
+static const struct squashfs_decompressor squashfs_lz4_comp_ops = {
+ NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 0
+};
+#endif
+
+#ifndef CONFIG_SQUASHFS_LZO
+static const struct squashfs_decompressor squashfs_lzo_comp_ops = {
+ NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0
+};
+#endif
+
+#ifndef CONFIG_SQUASHFS_XZ
+static const struct squashfs_decompressor squashfs_xz_comp_ops = {
+ NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0
+};
+#endif
+
+#ifndef CONFIG_SQUASHFS_ZLIB
+static const struct squashfs_decompressor squashfs_zlib_comp_ops = {
+ NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0
+};
+#endif
+
+#ifndef CONFIG_SQUASHFS_ZSTD
+static const struct squashfs_decompressor squashfs_zstd_comp_ops = {
+ NULL, NULL, NULL, NULL, ZSTD_COMPRESSION, "zstd", 0
+};
+#endif
+
+static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
+ NULL, NULL, NULL, NULL, 0, "unknown", 0
+};
+
+static const struct squashfs_decompressor *decompressor[] = {
+ &squashfs_zlib_comp_ops,
+ &squashfs_lz4_comp_ops,
+ &squashfs_lzo_comp_ops,
+ &squashfs_xz_comp_ops,
+ &squashfs_lzma_unsupported_comp_ops,
+ &squashfs_zstd_comp_ops,
+ &squashfs_unknown_comp_ops
+};
+
+
+const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
+{
+ int i;
+
+ for (i = 0; decompressor[i]->id; i++)
+ if (id == decompressor[i]->id)
+ break;
+
+ return decompressor[i];
+}
+
+
+static void *get_comp_opts(struct super_block *sb, unsigned short flags)
+{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ void *buffer = NULL, *comp_opts;
+ struct squashfs_page_actor *actor = NULL;
+ int length = 0;
+
+ /*
+ * Read decompressor specific options from file system if present
+ */
+ if (SQUASHFS_COMP_OPTS(flags)) {
+ buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (buffer == NULL) {
+ comp_opts = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ actor = squashfs_page_actor_init(&buffer, 1, 0);
+ if (actor == NULL) {
+ comp_opts = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ length = squashfs_read_data(sb,
+ sizeof(struct squashfs_super_block), 0, NULL, actor);
+
+ if (length < 0) {
+ comp_opts = ERR_PTR(length);
+ goto out;
+ }
+ }
+
+ comp_opts = squashfs_comp_opts(msblk, buffer, length);
+
+out:
+ kfree(actor);
+ kfree(buffer);
+ return comp_opts;
+}
+
+
+void *squashfs_decompressor_setup(struct super_block *sb, unsigned short flags)
+{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ void *stream, *comp_opts = get_comp_opts(sb, flags);
+
+ if (IS_ERR(comp_opts))
+ return comp_opts;
+
+ stream = squashfs_decompressor_create(msblk, comp_opts);
+ if (IS_ERR(stream))
+ kfree(comp_opts);
+
+ return stream;
+}