[CRYPTO] cryptd: Add software async crypto daemon

This patch adds the cryptd module which is a template that takes a
synchronous software crypto algorithm and converts it to an asynchronous
one by executing it in a kernel thread.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/Kconfig b/crypto/Kconfig
index a20a3f1..620e14c 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -175,6 +175,15 @@
 	  The first 128, 192 or 256 bits in the key are used for AES and the
 	  rest is used to tie each cipher block to its logical position.
 
+config CRYPTO_CRYPTD
+	tristate "Software async crypto daemon"
+	select CRYPTO_ABLKCIPHER
+	select CRYPTO_MANAGER
+	help
+	  This is a generic software asynchronous crypto daemon that
+	  converts an arbitrary synchronous software crypto algorithm
+	  into an asynchronous algorithm that executes in a kernel thread.
+
 config CRYPTO_DES
 	tristate "DES and Triple DES EDE cipher algorithms"
 	select CRYPTO_ALGAPI