From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Richter Subject: Re: ext4_lazyinit_thread: 'ret' may be used uninitialized in this function Date: Tue, 02 Nov 2010 20:49:25 +0100 Message-ID: <4CD06B45.2070704@s5r6.in-berlin.de> References: <20101102182911.GE25614@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kevin granade , "Ted Ts'o" , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org To: Lukas Czerner Return-path: Received: from einhorn.in-berlin.de ([192.109.42.8]:56082 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752242Ab0KBTto (ORCPT ); Tue, 2 Nov 2010 15:49:44 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: Lukas Czerner wrote: > On Tue, 2 Nov 2010, kevin granade wrote: >> + if (time_after_eq(jiffies, elr->lr_next_sched) && >> + ext4_run_li_request(elr) != 0) { >> + /* error, remove the lazy_init job */ >> + ext4_remove_li_request(elr); >> + continue; >> } >> >> if (time_before(elr->lr_next_sched, next_wakeup)) >> -- >> >> Though obviously it's a pretty subjective style issue. >> Kevin Granade > > Hmm this relies on the fact that if the first part of the condition > would not be true, the second part (after and) would never be invoked, > however I am not really sure that we can rely on that on every > architecture, or can we ? It is not about architecture but a C language feature. It is relied upon everywhere in the kernel. For example, if (p != NULL && p->m == something) { ... is very common. The || operator has the same property: Evaluation stops as soon as the end result is known. I do not know since when this minimum evaluation feature is guaranteed in the language, but it has to be ages now. (This is not an endorsement of one or the other coding of the patch. :-) -- Stefan Richter -=====-==-=- =-== ---=- http://arcgraph.de/sr/