Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752825Ab2EAUTP (ORCPT ); Tue, 1 May 2012 16:19:15 -0400 Received: from mail-gy0-f174.google.com ([209.85.160.174]:63319 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750713Ab2EAUTO convert rfc822-to-8bit (ORCPT ); Tue, 1 May 2012 16:19:14 -0400 MIME-Version: 1.0 In-Reply-To: <4FA04373.6090100@redhat.com> References: <1335894655-11398-1-git-send-email-dledford@redhat.com> <4FA04131.2040004@gmail.com> <4FA04373.6090100@redhat.com> From: KOSAKI Motohiro Date: Tue, 1 May 2012 16:18:52 -0400 Message-ID: Subject: Re: [Patch 3/4] ipc/mqueue: strengthen checks on mqueue creation To: Doug Ledford Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, sfr@canb.auug.org.au Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1313 Lines: 23 >> But ENOMEM is more inaccurate. It almostly is used for kmalloc failure. > > I chose ENOMEM for that particular error because above there we have > checked the passed in arguments to make sure that they don't violate our > allowances for max message or max message size. ?If we violate either of > those items, we return EINVAL. ?In this case, neither of the values is > invalid, it's just that together they make an overly large allocation. > I would see that as more helpful to a programmer than EINVAL when the > values are within the maximums allowed. ?At least with ENOMEM the > programmer knows they have to reduce their combined message size and > message count in order to get things working. Incorrect. When ENOMEM is returned, programmers can't know which problem was happen 1) kernel has real memory starvation or 2) queue limitation exceed was happen. The problem is, you introduced new overloaded error code for avoiding overload error code. It doesn't make sense. My question was, why can't you choose no overload error code if you want accurate one? -- 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/