Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992435Ab2KNW1c (ORCPT ); Wed, 14 Nov 2012 17:27:32 -0500 Received: from mail-bk0-f46.google.com ([209.85.214.46]:57306 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933163Ab2KNW1a (ORCPT ); Wed, 14 Nov 2012 17:27:30 -0500 MIME-Version: 1.0 In-Reply-To: <20121114221544.GA3083@elliptictech.com> References: <1351796580-20600-1-git-send-email-nbowler@elliptictech.com> <20121114130500.250dd5b8.akpm@linux-foundation.org> <20121114221544.GA3083@elliptictech.com> Date: Wed, 14 Nov 2012 23:27:29 +0100 Message-ID: Subject: Re: [PATCH] scatterlist: don't BUG when we can trivially return a proper error. From: richard -rw- weinberger To: Nick Bowler Cc: Andrew Morton , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1609 Lines: 46 On Wed, Nov 14, 2012 at 11:15 PM, Nick Bowler wrote: > On 2012-11-14 13:05 -0800, Andrew Morton wrote: >> On Thu, 1 Nov 2012 15:03:00 -0400 >> Nick Bowler wrote: >> >> > There is absolutely no reason to crash the kernel when we have a >> > perfectly good return value already available to use for conveying >> > failure status. >> >> Yes, I suppose that's true. I don't see a case for BUGging the kernel >> here. > [...] >> > - BUG_ON(nents > max_ents); >> > + if (WARN_ON_ONCE(nents > max_ents)) >> > + return -E2BIG; >> > #endif >> >> OK, pet peeve: if this E2BIG gets returned to userspace, our poor user >> will look it up and see "Argument list too long; used when the >> arguments passed to a new program being executed with one of the exec >> functions occupy too much memory space". He then gets to spend half a >> day reviewing his code's exec() callsites! >> >> See? Although the error's name sounds like a nice match to the >> internal state, it isn't really a match at all and our use of it is >> misleading. >> >> Unfortunately there is no EKERNELSCREWEDUP, > > Well, maybe we should add it! :P > >> so we usually use EINVAL. > > Fair enough. I will prepare v2. But perhaps EOPNOTSUPP would be a > better fit? IMHO this would be even more confusing... -- Thanks, //richard -- 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/