[PATCH 7/7] lib/lzo: separate lzo-rle from lzo

[Dave Rodgman <dave.rodgman@arm.com>]

To prevent any issues with persistent data, separate lzo-rle
from lzo so that it is treated as a separate algorithm, and
lzo is still available.

Use lzo-rle as the default algorithm for
zram.

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
---
 Documentation/lzo.txt         |  12 ++-
 crypto/Makefile               |   2 +-
 crypto/lzo-rle.c              | 175 ++++++++++++++++++++++++++++++++++++++++++
 crypto/tcrypt.c               |   4 +-
 drivers/block/zram/zcomp.c    |   1 +
 drivers/block/zram/zram_drv.c |   2 +-
 include/linux/lzo.h           |   4 +
 lib/lzo/lzo1x_compress.c      |  42 +++++++---
 lib/lzo/lzodefs.h             |   3 +-
 9 files changed, 227 insertions(+), 18 deletions(-)
 create mode 100644 crypto/lzo-rle.c

diff --git a/Documentation/lzo.txt b/Documentation/lzo.txt
index 306c60344ca7..f79934225d8d 100644
--- a/Documentation/lzo.txt
+++ b/Documentation/lzo.txt
@@ -88,6 +88,10 @@ length encoding. This improves speed for data with many zeros, which is a
 common case for zram. This modifies the bitstream in a backwards compatible way
 (v1 can correctly decompress v0 compressed data, but v0 cannot read v1 data).
 
+For maximum compatibility, both versions are available under different names
+(lzo and lzo-rle). Differences in the encoding are noted in this document with
+e.g.: version 1 only.
+
 Byte sequences
 ==============
 
@@ -99,8 +103,8 @@ Byte sequences
                 invalid at this place.
 
       17      : bitstream version. If the first byte is 17, the next byte
-                gives the bitstream version. If the first byte is not 17,
-                the bitstream version is 0.
+                gives the bitstream version (version 1 only). If the first byte
+                is not 17, the bitstream version is 0.
 
       18..21  : copy 0..3 literals
                 state = (byte - 17) = 0..3  [ copy <state> literals ]
@@ -154,8 +158,8 @@ Byte sequences
            state = S (copy S literals after this block)
            End of stream is reached if distance == 16384
 
-        In version 1, this instruction is also used to encode a run of zeros if
-        distance = 0xbfff, i.e. H = 1 and the D bits are all 1.
+        In version 1 only, this instruction is also used to encode a run of
+        zeros if distance = 0xbfff, i.e. H = 1 and the D bits are all 1.
            In this case, it is followed by a fourth byte, X.
            run length = ((X << 3) | (0 0 0 0 0 L L L)) + 4.
 
diff --git a/crypto/Makefile b/crypto/Makefile
index 5e789dc2d4fd..23491b70e601 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -127,7 +127,7 @@ obj-$(CONFIG_CRYPTO_CRC32C) += crc32c_generic.o
 obj-$(CONFIG_CRYPTO_CRC32) += crc32_generic.o
 obj-$(CONFIG_CRYPTO_CRCT10DIF) += crct10dif_common.o crct10dif_generic.o
 obj-$(CONFIG_CRYPTO_AUTHENC) += authenc.o authencesn.o
-obj-$(CONFIG_CRYPTO_LZO) += lzo.o
+obj-$(CONFIG_CRYPTO_LZO) += lzo.o lzo-rle.o
 obj-$(CONFIG_CRYPTO_LZ4) += lz4.o
 obj-$(CONFIG_CRYPTO_LZ4HC) += lz4hc.o
 obj-$(CONFIG_CRYPTO_842) += 842.o
diff --git a/crypto/lzo-rle.c b/crypto/lzo-rle.c
new file mode 100644
index 000000000000..ea9c75b1db49
--- /dev/null
+++ b/crypto/lzo-rle.c
@@ -0,0 +1,175 @@
+/*
+ * 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/mm.h>
+#include <linux/lzo.h>
+#include <crypto/internal/scompress.h>
+
+struct lzorle_ctx {
+	void *lzorle_comp_mem;
+};
+
+static void *lzorle_alloc_ctx(struct crypto_scomp *tfm)
+{
+	void *ctx;
+
+	ctx = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	return ctx;
+}
+
+static int lzorle_init(struct crypto_tfm *tfm)
+{
+	struct lzorle_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	ctx->lzorle_comp_mem = lzorle_alloc_ctx(NULL);
+	if (IS_ERR(ctx->lzorle_comp_mem))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void lzorle_free_ctx(struct crypto_scomp *tfm, void *ctx)
+{
+	kvfree(ctx);
+}
+
+static void lzorle_exit(struct crypto_tfm *tfm)
+{
+	struct lzorle_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	lzorle_free_ctx(NULL, ctx->lzorle_comp_mem);
+}
+
+static int __lzorle_compress(const u8 *src, unsigned int slen,
+			  u8 *dst, unsigned int *dlen, void *ctx)
+{
+	size_t tmp_len = *dlen; /* size_t(ulong) <-> uint on 64 bit */
+	int err;
+
+	err = lzorle1x_1_compress(src, slen, dst, &tmp_len, ctx);
+
+	if (err != LZO_E_OK)
+		return -EINVAL;
+
+	*dlen = tmp_len;
+	return 0;
+}
+
+static int lzorle_compress(struct crypto_tfm *tfm, const u8 *src,
+			unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+	struct lzorle_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	return __lzorle_compress(src, slen, dst, dlen, ctx->lzorle_comp_mem);
+}
+
+static int lzorle_scompress(struct crypto_scomp *tfm, const u8 *src,
+			 unsigned int slen, u8 *dst, unsigned int *dlen,
+			 void *ctx)
+{
+	return __lzorle_compress(src, slen, dst, dlen, ctx);
+}
+
+static int __lzorle_decompress(const u8 *src, unsigned int slen,
+			    u8 *dst, unsigned int *dlen)
+{
+	int err;
+	size_t tmp_len = *dlen; /* size_t(ulong) <-> uint on 64 bit */
+
+	err = lzo1x_decompress_safe(src, slen, dst, &tmp_len);
+
+	if (err != LZO_E_OK)
+		return -EINVAL;
+
+	*dlen = tmp_len;
+	return 0;
+}
+
+static int lzorle_decompress(struct crypto_tfm *tfm, const u8 *src,
+			  unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+	return __lzorle_decompress(src, slen, dst, dlen);
+}
+
+static int lzorle_sdecompress(struct crypto_scomp *tfm, const u8 *src,
+			   unsigned int slen, u8 *dst, unsigned int *dlen,
+			   void *ctx)
+{
+	return __lzorle_decompress(src, slen, dst, dlen);
+}
+
+static struct crypto_alg alg = {
+	.cra_name		= "lzo-rle",
+	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,
+	.cra_ctxsize		= sizeof(struct lzorle_ctx),
+	.cra_module		= THIS_MODULE,
+	.cra_init		= lzorle_init,
+	.cra_exit		= lzorle_exit,
+	.cra_u			= { .compress = {
+	.coa_compress		= lzorle_compress,
+	.coa_decompress		= lzorle_decompress } }
+};
+
+static struct scomp_alg scomp = {
+	.alloc_ctx		= lzorle_alloc_ctx,
+	.free_ctx		= lzorle_free_ctx,
+	.compress		= lzorle_scompress,
+	.decompress		= lzorle_sdecompress,
+	.base			= {
+		.cra_name	= "lzo-rle",
+		.cra_driver_name = "lzo-rle-scomp",
+		.cra_module	 = THIS_MODULE,
+	}
+};
+
+static int __init lzorle_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;
+	}
+
+	return ret;
+}
+
+static void __exit lzorle_mod_fini(void)
+{
+	crypto_unregister_alg(&alg);
+	crypto_unregister_scomp(&scomp);
+}
+
+module_init(lzorle_mod_init);
+module_exit(lzorle_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZO-RLE Compression Algorithm");
+MODULE_ALIAS_CRYPTO("lzo-rle");
diff --git a/crypto/tcrypt.c b/crypto/tcrypt.c
index 0590a9204562..c1c56c9771cf 100644
--- a/crypto/tcrypt.c
+++ b/crypto/tcrypt.c
@@ -76,8 +76,8 @@ static char *check[] = {
 	"cast6", "arc4", "michael_mic", "deflate", "crc32c", "tea", "xtea",
 	"khazad", "wp512", "wp384", "wp256", "tnepres", "xeta",  "fcrypt",
 	"camellia", "seed", "salsa20", "rmd128", "rmd160", "rmd256", "rmd320",
-	"lzo", "cts", "sha3-224", "sha3-256", "sha3-384", "sha3-512",
-	"streebog256", "streebog512",
+	"lzo", "lzo-rle", "cts", "sha3-224", "sha3-256", "sha3-384",
+	"sha3-512", "streebog256", "streebog512",
 	NULL
 };
 
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 4ed0a78fdc09..4d9a38890965 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -20,6 +20,7 @@
 
 static const char * const backends[] = {
 	"lzo",
+	"lzo-rle",
 #if IS_ENABLED(CONFIG_CRYPTO_LZ4)
 	"lz4",
 #endif
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 4879595200e1..984072868422 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -41,7 +41,7 @@ static DEFINE_IDR(zram_index_idr);
 static DEFINE_MUTEX(zram_index_mutex);
 
 static int zram_major;
-static const char *default_compressor = "lzo";
+static const char *default_compressor = "lzo-rle";
 
 /* Module params (documentation at end) */
 static unsigned int num_devices = 1;
diff --git a/include/linux/lzo.h b/include/linux/lzo.h
index 547a86c71e1b..e95c7d1092b2 100644
--- a/include/linux/lzo.h
+++ b/include/linux/lzo.h
@@ -24,6 +24,10 @@
 int lzo1x_1_compress(const unsigned char *src, size_t src_len,
 		     unsigned char *dst, size_t *dst_len, void *wrkmem);
 
+/* This requires 'wrkmem' of size LZO1X_1_MEM_COMPRESS */
+int lzorle1x_1_compress(const unsigned char *src, size_t src_len,
+		     unsigned char *dst, size_t *dst_len, void *wrkmem);
+
 /* safe decompression with overrun testing */
 int lzo1x_decompress_safe(const unsigned char *src, size_t src_len,
 			  unsigned char *dst, size_t *dst_len);
diff --git a/lib/lzo/lzo1x_compress.c b/lib/lzo/lzo1x_compress.c
index fa8d4ff38531..1a1cd5e84391 100644
--- a/lib/lzo/lzo1x_compress.c
+++ b/lib/lzo/lzo1x_compress.c
@@ -20,7 +20,8 @@
 static noinline size_t
 lzo1x_1_do_compress(const unsigned char *in, size_t in_len,
 		    unsigned char *out, size_t *out_len,
-		    size_t ti, void *wrkmem, signed char *state_offset)
+		    size_t ti, void *wrkmem, signed char *state_offset,
+		    const unsigned char bitstream_version)
 {
 	const unsigned char *ip;
 	unsigned char *op;
@@ -46,7 +47,7 @@ lzo1x_1_do_compress(const unsigned char *in, size_t in_len,
 			break;
 		dv = get_unaligned_le32(ip);
 
-		if (dv == 0) {
+		if (dv == 0 && bitstream_version) {
 			const unsigned char *ir = ip + 4;
 			const unsigned char *limit = ip_end
 				< (ip + MAX_ZERO_RUN_LENGTH + 1)
@@ -282,30 +283,36 @@ lzo1x_1_do_compress(const unsigned char *in, size_t in_len,
 	return in_end - (ii - ti);
 }
 
-int lzo1x_1_compress(const unsigned char *in, size_t in_len,
+int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
 		     unsigned char *out, size_t *out_len,
-		     void *wrkmem)
+		     void *wrkmem, const unsigned char bitstream_version)
 {
 	const unsigned char *ip = in;
 	unsigned char *op = out;
 	size_t l = in_len;
 	size_t t = 0;
 	signed char state_offset = -2;
+	unsigned int m4_max_offset;
 
 	// LZO v0 will never write 17 as first byte,
 	// so this is used to version the bitstream
-	*op++ = 17;
-	*op++ = LZO_VERSION;
+	if (bitstream_version > 0) {
+		*op++ = 17;
+		*op++ = bitstream_version;
+		m4_max_offset = M4_MAX_OFFSET_V1;
+	} else {
+		m4_max_offset = M4_MAX_OFFSET_V0;
+	}
 
 	while (l > 20) {
-		size_t ll = l <= (M4_MAX_OFFSET + 1) ? l : (M4_MAX_OFFSET + 1);
+		size_t ll = l <= (m4_max_offset + 1) ? l : (m4_max_offset + 1);
 		uintptr_t ll_end = (uintptr_t) ip + ll;
 		if ((ll_end + ((t + ll) >> 5)) <= ll_end)
 			break;
 		BUILD_BUG_ON(D_SIZE * sizeof(lzo_dict_t) > LZO1X_1_MEM_COMPRESS);
 		memset(wrkmem, 0, D_SIZE * sizeof(lzo_dict_t));
-		t = lzo1x_1_do_compress(ip, ll, op, out_len,
-					t, wrkmem, &state_offset);
+		t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem,
+					&state_offset, bitstream_version);
 		ip += ll;
 		op += *out_len;
 		l  -= ll;
@@ -348,7 +355,24 @@ int lzo1x_1_compress(const unsigned char *in, size_t in_len,
 	*out_len = op - out;
 	return LZO_E_OK;
 }
+
+int lzo1x_1_compress(const unsigned char *in, size_t in_len,
+		     unsigned char *out, size_t *out_len,
+		     void *wrkmem)
+{
+	return lzogeneric1x_1_compress(in, in_len, out, out_len, wrkmem, 0);
+}
+
+int lzorle1x_1_compress(const unsigned char *in, size_t in_len,
+		     unsigned char *out, size_t *out_len,
+		     void *wrkmem)
+{
+	return lzogeneric1x_1_compress(in, in_len, out, out_len,
+				       wrkmem, LZO_VERSION);
+}
+
 EXPORT_SYMBOL_GPL(lzo1x_1_compress);
+EXPORT_SYMBOL_GPL(lzorle1x_1_compress);
 
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("LZO1X-1 Compressor");
diff --git a/lib/lzo/lzodefs.h b/lib/lzo/lzodefs.h
index 682359058b3c..c0657441a35d 100644
--- a/lib/lzo/lzodefs.h
+++ b/lib/lzo/lzodefs.h
@@ -52,7 +52,8 @@
 #define M1_MAX_OFFSET	0x0400
 #define M2_MAX_OFFSET	0x0800
 #define M3_MAX_OFFSET	0x4000
-#define M4_MAX_OFFSET	0xbffe
+#define M4_MAX_OFFSET_V0	0xbfff
+#define M4_MAX_OFFSET_V1	0xbffe
 
 #define M1_MIN_LEN	2
 #define M1_MAX_LEN	2
-- 
2.16.4