crypto: lrw - add interface for parallelized cipher implementions

Export gf128mul table initialization routines and add lrw_crypt() function
that can be used by cipher implementations that can benefit from parallelized
cipher operations.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 43 insertions, 0 deletions

diff --git a/include/crypto/lrw.h b/include/crypto/lrw.h
new file mode 100644
index 000000000000..25a2c8716375
--- /dev/null
+++ b/include/crypto/lrw.h
@@ -0,0 +1,43 @@
+#ifndef _CRYPTO_LRW_H
+#define _CRYPTO_LRW_H
+
+#include <crypto/b128ops.h>
+
+struct scatterlist;
+struct gf128mul_64k;
+struct blkcipher_desc;
+
+#define LRW_BLOCK_SIZE 16
+
+struct lrw_table_ctx {
+        /* optimizes multiplying a random (non incrementing, as at the
+         * start of a new sector) value with key2, we could also have
+         * used 4k optimization tables or no optimization at all. In the
+         * latter case we would have to store key2 here */
+        struct gf128mul_64k *table;
+        /* stores:
+         *  key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 },
+         *  key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 }
+         *  key2*{ 0,0,...1,1,1,1,1 }, etc
+         * needed for optimized multiplication of incrementing values
+         * with key2 */
+        be128 mulinc[128];
+};
+
+int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak);
+void lrw_free_table(struct lrw_table_ctx *ctx);
+
+struct lrw_crypt_req {
+        be128 *tbuf;
+        unsigned int tbuflen;
+
+        struct lrw_table_ctx *table_ctx;
+        void *crypt_ctx;
+        void (*crypt_fn)(void *ctx, u8 *blks, unsigned int nbytes);
+};
+
+int lrw_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+              struct scatterlist *src, unsigned int nbytes,
+              struct lrw_crypt_req *req);
+
+#endif  /* _CRYPTO_LRW_H */