sgsn: Remove explicit sgsn_instance parameters

Currently the function in sgsn_auth.c either have an sgsn_config or
an sgsn_instance parameter. Since then global sgsn variable is
already being used in that file and since other parts of the SGSN
related code also rely on a global sgsn singleton, these parameters
pretend to provide a flexibility that is not really supported.

Therefore this patch removes these parameters except for the ACL
related functions, which do not call code that uses the sgsn
variable.

Sponsored-by: On-Waves ehf
diff --git a/openbsc/src/gprs/sgsn_auth.c b/openbsc/src/gprs/sgsn_auth.c
index 0407e9e..eb85d45 100644
--- a/openbsc/src/gprs/sgsn_auth.c
+++ b/openbsc/src/gprs/sgsn_auth.c
@@ -34,9 +34,9 @@
 
 const struct value_string *sgsn_auth_state_names = auth_state_names;
 
-void sgsn_auth_init(struct sgsn_instance *sgi)
+void sgsn_auth_init(void)
 {
-	INIT_LLIST_HEAD(&sgi->cfg.imsi_acl);
+	INIT_LLIST_HEAD(&sgsn->cfg.imsi_acl);
 }
 
 /* temporary IMSI ACL hack */
@@ -81,8 +81,7 @@
 	return 0;
 }
 
-enum sgsn_auth_state sgsn_auth_state(struct sgsn_mm_ctx *mmctx,
-				     struct sgsn_config *cfg)
+enum sgsn_auth_state sgsn_auth_state(struct sgsn_mm_ctx *mmctx)
 {
 	char mccmnc[16];
 	int check_net = 0;
@@ -125,22 +124,22 @@
 	return SGSN_AUTH_REJECTED;
 }
 
-int sgsn_auth_request(struct sgsn_mm_ctx *mmctx, struct sgsn_config *cfg)
+int sgsn_auth_request(struct sgsn_mm_ctx *mmctx)
 {
 	/* TODO: Add remote subscriber update requests here */
 
-	sgsn_auth_update(mmctx, sgsn);
+	sgsn_auth_update(mmctx);
 
 	return 0;
 }
 
-void sgsn_auth_update(struct sgsn_mm_ctx *mmctx, struct sgsn_instance *sgi)
+void sgsn_auth_update(struct sgsn_mm_ctx *mmctx)
 {
 	enum sgsn_auth_state auth_state;
 
 	LOGMMCTXP(LOGL_DEBUG, mmctx, "Updating authorization\n");
 
-	auth_state = sgsn_auth_state(mmctx, &sgi->cfg);
+	auth_state = sgsn_auth_state(mmctx);
 	if (auth_state == SGSN_AUTH_UNKNOWN) {
 		/* Reject requests since remote updates are NYI */
 		LOGMMCTXP(LOGL_ERROR, mmctx,