+--- a/crypto/Kconfig
++++ b/crypto/Kconfig
+@@ -924,6 +924,13 @@ config CRYPTO_LZO
+ help
+ This is the LZO algorithm.
+
++config CRYPTO_XZ
++ tristate "XZ compression algorithm"
++ select CRYPTO_ALGAPI
++ select XZ_DEC
++ help
++ This is the XZ algorithm. Only decompression is supported for now.
++
+ comment "Random Number Generation"
+
+ config CRYPTO_ANSI_CPRNG
+--- a/crypto/Makefile
++++ b/crypto/Makefile
+@@ -82,6 +82,7 @@ obj-$(CONFIG_CRYPTO_MICHAEL_MIC) += mich
+ obj-$(CONFIG_CRYPTO_CRC32C) += crc32c.o
+ obj-$(CONFIG_CRYPTO_AUTHENC) += authenc.o authencesn.o
+ obj-$(CONFIG_CRYPTO_LZO) += lzo.o
++obj-$(CONFIG_CRYPTO_XZ) += xz.o
+ obj-$(CONFIG_CRYPTO_RNG2) += rng.o
+ obj-$(CONFIG_CRYPTO_RNG2) += krng.o
+ obj-$(CONFIG_CRYPTO_ANSI_CPRNG) += ansi_cprng.o
+--- /dev/null
++++ b/crypto/xz.c
+@@ -0,0 +1,117 @@
++/*
++ * Cryptographic API.
++ *
++ * XZ decompression support.
++ *
++ * Copyright (c) 2012 Gabor Juhos <juhosg@openwrt.org>
++ *
++ * This program is free software; you can redistribute it and/or modify it
++ * under the terms of the GNU General Public License version 2 as published by
++ * the Free Software Foundation.
++ *
++ */
++#include <linux/init.h>
++#include <linux/module.h>
++#include <linux/crypto.h>
++#include <linux/xz.h>
++#include <linux/interrupt.h>
++#include <linux/mm.h>
++#include <linux/net.h>
++
++struct xz_comp_ctx {
++ struct xz_dec *decomp_state;
++ struct xz_buf decomp_buf;
++};
++
++static int crypto_xz_decomp_init(struct xz_comp_ctx *ctx)
++{
++ ctx->decomp_state = xz_dec_init(XZ_SINGLE, 0);
++ if (!ctx->decomp_state)
++ return -ENOMEM;
++
++ return 0;
++}
++
++static void crypto_xz_decomp_exit(struct xz_comp_ctx *ctx)
++{
++ xz_dec_end(ctx->decomp_state);
++}
++
++static int crypto_xz_init(struct crypto_tfm *tfm)
++{
++ struct xz_comp_ctx *ctx = crypto_tfm_ctx(tfm);
++
++ return crypto_xz_decomp_init(ctx);
++}
++
++static void crypto_xz_exit(struct crypto_tfm *tfm)
++{
++ struct xz_comp_ctx *ctx = crypto_tfm_ctx(tfm);
++
++ crypto_xz_decomp_exit(ctx);
++}
++
++static int crypto_xz_compress(struct crypto_tfm *tfm, const u8 *src,
++ unsigned int slen, u8 *dst, unsigned int *dlen)
++{
++ return -EOPNOTSUPP;
++}
++
++static int crypto_xz_decompress(struct crypto_tfm *tfm, const u8 *src,
++ unsigned int slen, u8 *dst, unsigned int *dlen)
++{
++ struct xz_comp_ctx *dctx = crypto_tfm_ctx(tfm);
++ struct xz_buf *xz_buf = &dctx->decomp_buf;
++ int ret;
++
++ memset(xz_buf, '\0', sizeof(struct xz_buf));
++
++ xz_buf->in = (u8 *) src;
++ xz_buf->in_pos = 0;
++ xz_buf->in_size = slen;
++ xz_buf->out = (u8 *) dst;
++ xz_buf->out_pos = 0;
++ xz_buf->out_size = *dlen;
++
++ ret = xz_dec_run(dctx->decomp_state, xz_buf);
++ if (ret != XZ_STREAM_END) {
++ ret = -EINVAL;
++ goto out;
++ }
++
++ *dlen = xz_buf->out_pos;
++ ret = 0;
++
++out:
++ return ret;
++}
++
++static struct crypto_alg crypto_xz_alg = {
++ .cra_name = "xz",
++ .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
++ .cra_ctxsize = sizeof(struct xz_comp_ctx),
++ .cra_module = THIS_MODULE,
++ .cra_list = LIST_HEAD_INIT(crypto_xz_alg.cra_list),
++ .cra_init = crypto_xz_init,
++ .cra_exit = crypto_xz_exit,
++ .cra_u = { .compress = {
++ .coa_compress = crypto_xz_compress,
++ .coa_decompress = crypto_xz_decompress } }
++};
++
++static int __init crypto_xz_mod_init(void)
++{
++ return crypto_register_alg(&crypto_xz_alg);
++}
++
++static void __exit crypto_xz_mod_exit(void)
++{
++ crypto_unregister_alg(&crypto_xz_alg);
++}
++
++module_init(crypto_xz_mod_init);
++module_exit(crypto_xz_mod_exit);
++
++MODULE_LICENSE("GPL v2");
++MODULE_DESCRIPTION("Crypto XZ decompression support");
++MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");