From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Mainly so that ubifs can use it.
Snappy is a better compressor in the same niche as LZO.
Only lightly tested so far. Experiences welcome.
Cc: herbert@xxxxxxxxxxxxxxxxxxx
Cc: dedekind1@xxxxxxxxx
Cc: adrian.hunter@xxxxxxxxx
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
crypto/Kconfig | 9 +++++
crypto/Makefile | 1 +
crypto/snappy.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 109 insertions(+), 0 deletions(-)
create mode 100644 crypto/snappy.c
diff --git a/crypto/Kconfig b/crypto/Kconfig
index ae27b753..2c85991 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -823,6 +823,15 @@ config CRYPTO_LZO
help
This is the LZO algorithm.
+config CRYPTO_SNAPPY
+ tristate "Snappy compression algorithm"
+ select CRYPTO_ALGAPI
+ select SNAPPY
+ help
+ snappy is a faster alternative to the lzo compression algorithm
+ with comparable compression. It is very fast on 64bit systems, but also
+ good on 32bit systems. It especially excels at already compressed data.
+
comment "Random Number Generation"
config CRYPTO_ANSI_CPRNG
diff --git a/crypto/Makefile b/crypto/Makefile
index ce5a813..cf92f6f 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -80,6 +80,7 @@ obj-$(CONFIG_CRYPTO_MICHAEL_MIC) += michael_mic.o
obj-$(CONFIG_CRYPTO_CRC32C) += crc32c.o
obj-$(CONFIG_CRYPTO_AUTHENC) += authenc.o authencesn.o
obj-$(CONFIG_CRYPTO_LZO) += lzo.o
+obj-$(CONFIG_CRYPTO_SNAPPY) += snappy.o
obj-$(CONFIG_CRYPTO_RNG2) += rng.o
obj-$(CONFIG_CRYPTO_RNG2) += krng.o
obj-$(CONFIG_CRYPTO_ANSI_CPRNG) += ansi_cprng.o
diff --git a/crypto/snappy.c b/crypto/snappy.c
new file mode 100644
index 0000000..2f44d30
--- /dev/null
+++ b/crypto/snappy.c
@@ -0,0 +1,99 @@
+/*
+ * Cryptographic API.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/crypto.h>
+#include <linux/vmalloc.h>
+#include <linux/snappy.h>
+
+struct snappy_ctx {
+ struct snappy_env env;
+};
+
+/* Only needed for compression actually */
+static int snappy_init(struct crypto_tfm *tfm)
+{
+ struct snappy_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ return snappy_init_env(&ctx->env);
+}
+
+static void snappy_exit(struct crypto_tfm *tfm)
+{
+ struct snappy_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ snappy_free_env(&ctx->env);
+}
+
+static int snp_compress(struct crypto_tfm *tfm, const u8 *src,
+ unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+ struct snappy_ctx *ctx = crypto_tfm_ctx(tfm);
+ size_t olen;
+ int err;
+
+ /* XXXX very pessimistic. check in snappy? */
+ if (*dlen < snappy_max_compressed_length(*dlen))
+ return -EINVAL;
+ err = snappy_compress(&ctx->env, src, slen, dst, &olen);
+ *dlen = olen;
+ return err;
+}
+
+static int snp_decompress(struct crypto_tfm *tfm, const u8 *src,
+ unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+ size_t ulen;
+
+ if (!snappy_uncompressed_length(src, slen, &ulen))
+ return -EIO;
+ if (*dlen < ulen)
+ return -EINVAL;
+ *dlen = ulen;
+ return snappy_uncompress(src, slen, dst) ? 0 : -EIO;
+}
+
+static struct crypto_alg alg = {
+ .cra_name = "snappy",
+ .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
+ .cra_ctxsize = sizeof(struct snappy_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(alg.cra_list),
+ .cra_init = snappy_init,
+ .cra_exit = snappy_exit,
+ .cra_u = { .compress = {
+ .coa_compress = snp_compress,
+ .coa_decompress = snp_decompress } }
+};
+
+static int __init snappy_mod_init(void)
+{
+ return crypto_register_alg(&alg);
+}
+
+static void __exit snappy_mod_fini(void)
+{
+ crypto_unregister_alg(&alg);
+}
+
+module_init(snappy_mod_init);
+module_exit(snappy_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Snappy Compression Algorithm");
--
1.7.4.4
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