Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935572Ab0BZIiv (ORCPT ); Fri, 26 Feb 2010 03:38:51 -0500 Received: from www262.sakura.ne.jp ([202.181.97.72]:50408 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935550Ab0BZIiu (ORCPT ); Fri, 26 Feb 2010 03:38:50 -0500 Message-Id: <201002260838.o1Q8cfr2068194@www262.sakura.ne.jp> Subject: Re: [RFC][PATCH] mm: Remove ZERO_SIZE_PTR. From: Tetsuo Handa To: kosaki.motohiro@jp.fujitsu.com Cc: linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Date: Fri, 26 Feb 2010 17:38:41 +0900 References: <201002260635.o1Q6ZYET040848@www262.sakura.ne.jp> <20100226155618.8D9E.A69D9226@jp.fujitsu.com> In-Reply-To: <20100226155618.8D9E.A69D9226@jp.fujitsu.com> Content-Type: text/plain; charset="ISO-2022-JP" X-Anti-Virus: K-Prox Anti-Virus Powered by Kaspersky, bases: 26022010 #3421565, status: clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 741 Lines: 22 KOSAKI Motohiro wrote: > > Therefore, at the cost of being unable to distinguish "NULL pointer > > dereference" and "ZERO_SIZE_PTR dereference" in some cases, removing > > ZERO_SIZE_PTR could reduce the risk of "ZERO_SIZE_PTR dereference" in many > > cases. > > NAK. yes, it could. but it is no worth. nobody want slower kernel. > This patch simplifies error checks of both callers/callees from ((unsigned long)(x) <= (unsigned long) 16) to !(x) . Why this patch makes the kernel slower? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/