crypto: zstd - Add zstd support

Adds zstd support to crypto and scompress. Only supports the default
level.

Previously we held off on this patch, since there weren't any users.
Now zram is ready for zstd support, but depends on CONFIG_CRYPTO_ZSTD,
which isn't defined until this patch is in. I also see a patch adding
zstd to pstore [0], which depends on crypto zstd.

[0] lkml.kernel.org/r/9c9416b2dff19f05fb4c35879aaa83d11ff72c92.1521626182.git.geliangtang@gmail.com

Signed-off-by: Nick Terrell <terrelln@fb.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 265 insertions, 0 deletions

diff --git a/crypto/zstd.c b/crypto/zstd.c
new file mode 100644
index 0000000..9a76b3e
--- /dev/null
+++ b/crypto/zstd.c
@@ -0,0 +1,265 @@
+/*
+ * Cryptographic API.
+ *
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * 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.
+ *
+ * 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.
+ */
+#include <linux/crypto.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/vmalloc.h>
+#include <linux/zstd.h>
+#include <crypto/internal/scompress.h>
+
+
+#define ZSTD_DEF_LEVEL	3
+
+struct zstd_ctx {
+	ZSTD_CCtx *cctx;
+	ZSTD_DCtx *dctx;
+	void *cwksp;
+	void *dwksp;
+};
+
+static ZSTD_parameters zstd_params(void)
+{
+	return ZSTD_getParams(ZSTD_DEF_LEVEL, 0, 0);
+}
+
+static int zstd_comp_init(struct zstd_ctx *ctx)
+{
+	int ret = 0;
+	const ZSTD_parameters params = zstd_params();
+	const size_t wksp_size = ZSTD_CCtxWorkspaceBound(params.cParams);
+
+	ctx->cwksp = vzalloc(wksp_size);
+	if (!ctx->cwksp) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ctx->cctx = ZSTD_initCCtx(ctx->cwksp, wksp_size);
+	if (!ctx->cctx) {
+		ret = -EINVAL;
+		goto out_free;
+	}
+out:
+	return ret;
+out_free:
+	vfree(ctx->cwksp);
+	goto out;
+}
+
+static int zstd_decomp_init(struct zstd_ctx *ctx)
+{
+	int ret = 0;
+	const size_t wksp_size = ZSTD_DCtxWorkspaceBound();
+
+	ctx->dwksp = vzalloc(wksp_size);
+	if (!ctx->dwksp) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ctx->dctx = ZSTD_initDCtx(ctx->dwksp, wksp_size);
+	if (!ctx->dctx) {
+		ret = -EINVAL;
+		goto out_free;
+	}
+out:
+	return ret;
+out_free:
+	vfree(ctx->dwksp);
+	goto out;
+}
+
+static void zstd_comp_exit(struct zstd_ctx *ctx)
+{
+	vfree(ctx->cwksp);
+	ctx->cwksp = NULL;
+	ctx->cctx = NULL;
+}
+
+static void zstd_decomp_exit(struct zstd_ctx *ctx)
+{
+	vfree(ctx->dwksp);
+	ctx->dwksp = NULL;
+	ctx->dctx = NULL;
+}
+
+static int __zstd_init(void *ctx)
+{
+	int ret;
+
+	ret = zstd_comp_init(ctx);
+	if (ret)
+		return ret;
+	ret = zstd_decomp_init(ctx);
+	if (ret)
+		zstd_comp_exit(ctx);
+	return ret;
+}
+
+static void *zstd_alloc_ctx(struct crypto_scomp *tfm)
+{
+	int ret;
+	struct zstd_ctx *ctx;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	ret = __zstd_init(ctx);
+	if (ret) {
+		kfree(ctx);
+		return ERR_PTR(ret);
+	}
+
+	return ctx;
+}
+
+static int zstd_init(struct crypto_tfm *tfm)
+{
+	struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	return __zstd_init(ctx);
+}
+
+static void __zstd_exit(void *ctx)
+{
+	zstd_comp_exit(ctx);
+	zstd_decomp_exit(ctx);
+}
+
+static void zstd_free_ctx(struct crypto_scomp *tfm, void *ctx)
+{
+	__zstd_exit(ctx);
+	kzfree(ctx);
+}
+
+static void zstd_exit(struct crypto_tfm *tfm)
+{
+	struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	__zstd_exit(ctx);
+}
+
+static int __zstd_compress(const u8 *src, unsigned int slen,
+			   u8 *dst, unsigned int *dlen, void *ctx)
+{
+	size_t out_len;
+	struct zstd_ctx *zctx = ctx;
+	const ZSTD_parameters params = zstd_params();
+
+	out_len = ZSTD_compressCCtx(zctx->cctx, dst, *dlen, src, slen, params);
+	if (ZSTD_isError(out_len))
+		return -EINVAL;
+	*dlen = out_len;
+	return 0;
+}
+
+static int zstd_compress(struct crypto_tfm *tfm, const u8 *src,
+			 unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+	struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	return __zstd_compress(src, slen, dst, dlen, ctx);
+}
+
+static int zstd_scompress(struct crypto_scomp *tfm, const u8 *src,
+			  unsigned int slen, u8 *dst, unsigned int *dlen,
+			  void *ctx)
+{
+	return __zstd_compress(src, slen, dst, dlen, ctx);
+}
+
+static int __zstd_decompress(const u8 *src, unsigned int slen,
+			     u8 *dst, unsigned int *dlen, void *ctx)
+{
+	size_t out_len;
+	struct zstd_ctx *zctx = ctx;
+
+	out_len = ZSTD_decompressDCtx(zctx->dctx, dst, *dlen, src, slen);
+	if (ZSTD_isError(out_len))
+		return -EINVAL;
+	*dlen = out_len;
+	return 0;
+}
+
+static int zstd_decompress(struct crypto_tfm *tfm, const u8 *src,
+			   unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+	struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	return __zstd_decompress(src, slen, dst, dlen, ctx);
+}
+
+static int zstd_sdecompress(struct crypto_scomp *tfm, const u8 *src,
+			    unsigned int slen, u8 *dst, unsigned int *dlen,
+			    void *ctx)
+{
+	return __zstd_decompress(src, slen, dst, dlen, ctx);
+}
+
+static struct crypto_alg alg = {
+	.cra_name		= "zstd",
+	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,
+	.cra_ctxsize		= sizeof(struct zstd_ctx),
+	.cra_module		= THIS_MODULE,
+	.cra_init		= zstd_init,
+	.cra_exit		= zstd_exit,
+	.cra_u			= { .compress = {
+	.coa_compress		= zstd_compress,
+	.coa_decompress		= zstd_decompress } }
+};
+
+static struct scomp_alg scomp = {
+	.alloc_ctx		= zstd_alloc_ctx,
+	.free_ctx		= zstd_free_ctx,
+	.compress		= zstd_scompress,
+	.decompress		= zstd_sdecompress,
+	.base			= {
+		.cra_name	= "zstd",
+		.cra_driver_name = "zstd-scomp",
+		.cra_module	 = THIS_MODULE,
+	}
+};
+
+static int __init zstd_mod_init(void)
+{
+	int ret;
+
+	ret = crypto_register_alg(&alg);
+	if (ret)
+		return ret;
+
+	ret = crypto_register_scomp(&scomp);
+	if (ret)
+		crypto_unregister_alg(&alg);
+
+	return ret;
+}
+
+static void __exit zstd_mod_fini(void)
+{
+	crypto_unregister_alg(&alg);
+	crypto_unregister_scomp(&scomp);
+}
+
+module_init(zstd_mod_init);
+module_exit(zstd_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Zstd Compression Algorithm");
+MODULE_ALIAS_CRYPTO("zstd");