From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755629AbaCKVZA (ORCPT ); Tue, 11 Mar 2014 17:25:00 -0400 Received: from mail-pd0-f181.google.com ([209.85.192.181]:43566 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754289AbaCKVY6 (ORCPT ); Tue, 11 Mar 2014 17:24:58 -0400 From: behanw@converseincode.com To: khali@linux-fr.org, rostedt@goodmis.org Cc: rusty@rustcorp.com.au, linux-kernel@vger.kernel.org, dwmw2@infradead.org, pageexec@freemail.hu, Mark Charlebois , Behan Webster Subject: [PATCH v3] module: LLVMLinux: Remove unused function warning from __param_check macro Date: Tue, 11 Mar 2014 14:24:51 -0700 Message-Id: <1394573091-4705-1-git-send-email-behanw@converseincode.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <87y50hw9go.fsf@rustcorp.com.au> References: <87y50hw9go.fsf@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mark Charlebois This code makes a compile time type check that is optimized away. Clang complains that it generates an unused function: linux/kernel/panic.c:471:1: warning: unused function '__check_panic' [-Wunused-function] core_param(panic, panic_timeout, int, 0644); ^ linux/moduleparam.h:283:2: note: expanded from macro 'core_param' param_check_##type(name, &(var)); \ ^ :87:1: note: expanded from here param_check_int ^ linux/moduleparam.h:369:34: note: expanded from macro 'param_check_int' #define param_check_int(name, p) __param_check(name, p, int) ^ linux/moduleparam.h:349:22: note: expanded from macro '__param_check' static inline type *__check_##name(void) { return(p); } ^ :88:1: note: expanded from here __check_panic GCC won't complain for a static inline function but would if it was just a static function. Adding the unused attribute to the function declaration removes the warning. Per request from Rusty Russell it is marked as __always_unused as the code is meant to be optimized away. This code works for both GCC and clang. Signed-off-by: Mark Charlebois Signed-off-by: Behan Webster --- include/linux/moduleparam.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index c3eb102..175f699 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -346,7 +346,7 @@ static inline void destroy_params(const struct kernel_param *params, /* The macros to do compile-time type checking stolen from Jakub Jelinek, who IIRC came up with this idea for the 2.4 module init code. */ #define __param_check(name, p, type) \ - static inline type *__check_##name(void) { return(p); } + static inline type __always_unused *__check_##name(void) { return(p); } extern struct kernel_param_ops param_ops_byte; extern int param_set_byte(const char *val, const struct kernel_param *kp); -- 1.8.3.2