xfrm: make xfrm_algo.c a module

By making this a standalone config option (auto-selected as needed),
selecting CRYPTO from here rather than from XFRM (which is boolean)
allows the core crypto code to become a module again even when XFRM=y.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/Kconfig

@@ -312,7 +312,7 @@ config SYN_COOKIES
 
 config INET_AH
 	tristate "IP: AH transformation"
-	select XFRM
+	select XFRM_ALGO
 	select CRYPTO
 	select CRYPTO_HMAC
 	select CRYPTO_MD5
@@ -324,7 +324,7 @@ config INET_AH
 
 config INET_ESP
 	tristate "IP: ESP transformation"
-	select XFRM
+	select XFRM_ALGO
 	select CRYPTO
 	select CRYPTO_AUTHENC
 	select CRYPTO_HMAC

net/ipv6/Kconfig

@@ -69,7 +69,7 @@ config IPV6_OPTIMISTIC_DAD
 
 config INET6_AH
 	tristate "IPv6: AH transformation"
-	select XFRM
+	select XFRM_ALGO
 	select CRYPTO
 	select CRYPTO_HMAC
 	select CRYPTO_MD5
@@ -81,7 +81,7 @@ config INET6_AH
 
 config INET6_ESP
 	tristate "IPv6: ESP transformation"
-	select XFRM
+	select XFRM_ALGO
 	select CRYPTO
 	select CRYPTO_AUTHENC
 	select CRYPTO_HMAC

net/xfrm/Kconfig

@@ -3,12 +3,17 @@
 #
 config XFRM
        bool
-       select CRYPTO
        depends on NET
 
+config XFRM_ALGO
+	tristate
+	select XFRM
+	select CRYPTO
+
 config XFRM_USER
 	tristate "Transformation user configuration interface"
-	depends on INET && XFRM
+	depends on INET
+	select XFRM_ALGO
 	---help---
 	  Support for Transformation(XFRM) user configuration interface
 	  like IPsec used by native Linux tools.
@@ -48,13 +53,13 @@ config XFRM_STATISTICS
 
 config XFRM_IPCOMP
 	tristate
-	select XFRM
+	select XFRM_ALGO
 	select CRYPTO
 	select CRYPTO_DEFLATE
 
 config NET_KEY
 	tristate "PF_KEY sockets"
-	select XFRM
+	select XFRM_ALGO
 	---help---
 	  PF_KEYv2 socket family, compatible to KAME ones.
 	  They are required if you are going to use IPsec tools ported

net/xfrm/Makefile

@@ -3,8 +3,9 @@
 #
 
 obj-$(CONFIG_XFRM) := xfrm_policy.o xfrm_state.o xfrm_hash.o \
-		      xfrm_input.o xfrm_output.o xfrm_algo.o \
+		      xfrm_input.o xfrm_output.o \
 		      xfrm_sysctl.o xfrm_replay.o
 obj-$(CONFIG_XFRM_STATISTICS) += xfrm_proc.o
+obj-$(CONFIG_XFRM_ALGO) += xfrm_algo.o
 obj-$(CONFIG_XFRM_USER) += xfrm_user.o
 obj-$(CONFIG_XFRM_IPCOMP) += xfrm_ipcomp.o

net/xfrm/xfrm_algo.c

@@ -752,3 +752,5 @@ void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
 }
 EXPORT_SYMBOL_GPL(pskb_put);
 #endif
+
+MODULE_LICENSE("GPL");