lib: digital signature config option name change

It was reported that DIGSIG is confusing name for digital signature
module. It was suggested to rename DIGSIG to SIGNATURE.
Requested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Suggested-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: NJames Morris <jmorris@namei.org>

include/linux/digsig.h

@@ -46,7 +46,7 @@ struct signature_hdr {
 	char		mpi[0];
 } __packed;
 
-#if defined(CONFIG_DIGSIG) || defined(CONFIG_DIGSIG_MODULE)
+#if defined(CONFIG_SIGNATURE) || defined(CONFIG_SIGNATURE_MODULE)
 
 int digsig_verify(struct key *keyring, const char *sig, int siglen,
 					const char *digest, int digestlen);
@@ -59,6 +59,6 @@ static inline int digsig_verify(struct key *keyring, const char *sig,
 	return -EOPNOTSUPP;
 }
 
-#endif /* CONFIG_DIGSIG */
+#endif /* CONFIG_SIGNATURE */
 
 #endif /* _DIGSIG_H */

lib/Kconfig

@@ -302,7 +302,7 @@ config MPILIB_EXTRA
 	  This code in unnecessary for RSA digital signature verification,
 	  and can be compiled if needed.
 
-config DIGSIG
+config SIGNATURE
 	tristate "In-kernel signature checker"
 	depends on KEYS
 	select MPILIB

lib/Makefile

@@ -119,7 +119,7 @@ obj-$(CONFIG_CORDIC) += cordic.o
 obj-$(CONFIG_DQL) += dynamic_queue_limits.o
 
 obj-$(CONFIG_MPILIB) += mpi/
-obj-$(CONFIG_DIGSIG) += digsig.o
+obj-$(CONFIG_SIGNATURE) += digsig.o
 
 hostprogs-y	:= gen_crc32table
 clean-files	:= crc32table.h

security/integrity/Kconfig

@@ -7,7 +7,7 @@ config INTEGRITY_DIGSIG
 	boolean "Digital signature verification using multiple keyrings"
 	depends on INTEGRITY && KEYS
 	default n
-	select DIGSIG
+	select SIGNATURE
 	help
 	  This option enables digital signature verification support
 	  using multiple keyrings. It defines separate keyrings for each