sunrpc: Simplify auth_unix now that everything is a kgid_t

In unx_create_cred directly assign gids from acred->group_info
to cred->uc_gids.

In unx_match directly compare uc_gids with group_info.

Now that both group_info and unx_cred gids are stored as kgids
this is valid and the extra layer of translation can be removed.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

net/sunrpc/auth_unix.c

@@ -79,11 +79,8 @@ unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 		groups = NFS_NGROUPS;
 
 	cred->uc_gid = acred->gid;
-	for (i = 0; i < groups; i++) {
-		gid_t gid;
-		gid = from_kgid(&init_user_ns, GROUP_AT(acred->group_info, i));
-		cred->uc_gids[i] = gid;
-	}
+	for (i = 0; i < groups; i++)
+		cred->uc_gids[i] = GROUP_AT(acred->group_info, i);
 	if (i < NFS_NGROUPS)
 		cred->uc_gids[i] = INVALID_GID;
 
@@ -130,12 +127,9 @@ unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
 		groups = acred->group_info->ngroups;
 	if (groups > NFS_NGROUPS)
 		groups = NFS_NGROUPS;
-	for (i = 0; i < groups ; i++) {
-		gid_t gid;
-		gid = from_kgid(&init_user_ns, GROUP_AT(acred->group_info, i));
-		if (cred->uc_gids[i] != gid)
+	for (i = 0; i < groups ; i++)
+		if (!gid_eq(cred->uc_gids[i], GROUP_AT(acred->group_info, i)))
 			return 0;
-	}
 	if (groups < NFS_NGROUPS &&
 	    cred->uc_gids[groups] != INVALID_GID)
 		return 0;