v4.19.13 snapshot.
diff --git a/fs/squashfs/xz_wrapper.c b/fs/squashfs/xz_wrapper.c
new file mode 100644
index 0000000..6bfaef7
--- /dev/null
+++ b/fs/squashfs/xz_wrapper.c
@@ -0,0 +1,193 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+ * 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.
+ *
+ * xz_wrapper.c
+ */
+
+
+#include <linux/mutex.h>
+#include <linux/buffer_head.h>
+#include <linux/slab.h>
+#include <linux/xz.h>
+#include <linux/bitops.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+#include "decompressor.h"
+#include "page_actor.h"
+
+struct squashfs_xz {
+ struct xz_dec *state;
+ struct xz_buf buf;
+};
+
+struct disk_comp_opts {
+ __le32 dictionary_size;
+ __le32 flags;
+};
+
+struct comp_opts {
+ int dict_size;
+};
+
+static void *squashfs_xz_comp_opts(struct squashfs_sb_info *msblk,
+ void *buff, int len)
+{
+ struct disk_comp_opts *comp_opts = buff;
+ struct comp_opts *opts;
+ int err = 0, n;
+
+ opts = kmalloc(sizeof(*opts), GFP_KERNEL);
+ if (opts == NULL) {
+ err = -ENOMEM;
+ goto out2;
+ }
+
+ if (comp_opts) {
+ /* check compressor options are the expected length */
+ if (len < sizeof(*comp_opts)) {
+ err = -EIO;
+ goto out;
+ }
+
+ opts->dict_size = le32_to_cpu(comp_opts->dictionary_size);
+
+ /* the dictionary size should be 2^n or 2^n+2^(n+1) */
+ n = ffs(opts->dict_size) - 1;
+ if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) +
+ (1 << (n + 1))) {
+ err = -EIO;
+ goto out;
+ }
+ } else
+ /* use defaults */
+ opts->dict_size = max_t(int, msblk->block_size,
+ SQUASHFS_METADATA_SIZE);
+
+ return opts;
+
+out:
+ kfree(opts);
+out2:
+ return ERR_PTR(err);
+}
+
+
+static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff)
+{
+ struct comp_opts *comp_opts = buff;
+ struct squashfs_xz *stream;
+ int err;
+
+ stream = kmalloc(sizeof(*stream), GFP_KERNEL);
+ if (stream == NULL) {
+ err = -ENOMEM;
+ goto failed;
+ }
+
+ stream->state = xz_dec_init(XZ_PREALLOC, comp_opts->dict_size);
+ if (stream->state == NULL) {
+ kfree(stream);
+ err = -ENOMEM;
+ goto failed;
+ }
+
+ return stream;
+
+failed:
+ ERROR("Failed to initialise xz decompressor\n");
+ return ERR_PTR(err);
+}
+
+
+static void squashfs_xz_free(void *strm)
+{
+ struct squashfs_xz *stream = strm;
+
+ if (stream) {
+ xz_dec_end(stream->state);
+ kfree(stream);
+ }
+}
+
+
+static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
+ struct buffer_head **bh, int b, int offset, int length,
+ struct squashfs_page_actor *output)
+{
+ enum xz_ret xz_err;
+ int avail, total = 0, k = 0;
+ struct squashfs_xz *stream = strm;
+
+ xz_dec_reset(stream->state);
+ stream->buf.in_pos = 0;
+ stream->buf.in_size = 0;
+ stream->buf.out_pos = 0;
+ stream->buf.out_size = PAGE_SIZE;
+ stream->buf.out = squashfs_first_page(output);
+
+ do {
+ if (stream->buf.in_pos == stream->buf.in_size && k < b) {
+ avail = min(length, msblk->devblksize - offset);
+ length -= avail;
+ stream->buf.in = bh[k]->b_data + offset;
+ stream->buf.in_size = avail;
+ stream->buf.in_pos = 0;
+ offset = 0;
+ }
+
+ if (stream->buf.out_pos == stream->buf.out_size) {
+ stream->buf.out = squashfs_next_page(output);
+ if (stream->buf.out != NULL) {
+ stream->buf.out_pos = 0;
+ total += PAGE_SIZE;
+ }
+ }
+
+ xz_err = xz_dec_run(stream->state, &stream->buf);
+
+ if (stream->buf.in_pos == stream->buf.in_size && k < b)
+ put_bh(bh[k++]);
+ } while (xz_err == XZ_OK);
+
+ squashfs_finish_page(output);
+
+ if (xz_err != XZ_STREAM_END || k < b)
+ goto out;
+
+ return total + stream->buf.out_pos;
+
+out:
+ for (; k < b; k++)
+ put_bh(bh[k]);
+
+ return -EIO;
+}
+
+const struct squashfs_decompressor squashfs_xz_comp_ops = {
+ .init = squashfs_xz_init,
+ .comp_opts = squashfs_xz_comp_opts,
+ .free = squashfs_xz_free,
+ .decompress = squashfs_xz_uncompress,
+ .id = XZ_COMPRESSION,
+ .name = "xz",
+ .supported = 1
+};