Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754208AbcCUXOv (ORCPT ); Mon, 21 Mar 2016 19:14:51 -0400 Received: from mail-wm0-f44.google.com ([74.125.82.44]:34961 "EHLO mail-wm0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751005AbcCUXOu (ORCPT ); Mon, 21 Mar 2016 19:14:50 -0400 From: Rasmus Villemoes To: Oleg Nesterov , Prarit Bhargava , Rusty Russell Cc: Andrew Morton , Rasmus Villemoes , linux-kernel@vger.kernel.org Subject: [PATCH resend] init/main.c: Simplify initcall_blacklisted() Date: Tue, 22 Mar 2016 00:14:25 +0100 Message-Id: <1458602066-15255-1-git-send-email-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.1.4 In-Reply-To: <54BEA0EE.10304@redhat.com> References: <54BEA0EE.10304@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1456 Lines: 48 Using kasprintf to get the function name makes us look up the name twice, along with all the vsnprintf overhead of parsing the format string etc. It also means there is an allocation failure case to deal with. Since symbol_string in vsprintf.c would anyway allocate an array of size KSYM_SYMBOL_LEN on the stack, that might as well be done up here. Moreover, since this is a debug feature and the blacklisted_initcalls list is usually empty, we might as well test that and thus avoid looking up the symbol name even once in the common case. Signed-off-by: Rasmus Villemoes --- init/main.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/init/main.c b/init/main.c index b3c6e363ae18..d76d94cd537c 100644 --- a/init/main.c +++ b/init/main.c @@ -706,21 +706,20 @@ static int __init initcall_blacklist(char *str) static bool __init_or_module initcall_blacklisted(initcall_t fn) { struct blacklist_entry *entry; - char *fn_name; + char fn_name[KSYM_SYMBOL_LEN]; - fn_name = kasprintf(GFP_KERNEL, "%pf", fn); - if (!fn_name) + if (list_empty(&blacklisted_initcalls)) return false; + sprint_symbol_no_offset(fn_name, (unsigned long)fn); + list_for_each_entry(entry, &blacklisted_initcalls, next) { if (!strcmp(fn_name, entry->buf)) { pr_debug("initcall %s blacklisted\n", fn_name); - kfree(fn_name); return true; } } - kfree(fn_name); return false; } #else -- 2.1.4