Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753143AbZLaTXj (ORCPT ); Thu, 31 Dec 2009 14:23:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752976AbZLaTXj (ORCPT ); Thu, 31 Dec 2009 14:23:39 -0500 Received: from astoria.ccjclearline.com ([64.235.106.9]:46525 "EHLO astoria.ccjclearline.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752882AbZLaTXi (ORCPT ); Thu, 31 Dec 2009 14:23:38 -0500 Date: Thu, 31 Dec 2009 14:23:02 -0500 (EST) From: "Robert P. J. Day" X-X-Sender: rpjday@localhost To: Linux Kernel Mailing List Subject: Re: backwards busy wait using "time_before()"?? In-Reply-To: Message-ID: References: User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - astoria.ccjclearline.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - crashcourse.ca X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2324 Lines: 59 On Thu, 31 Dec 2009, Robert P. J. Day wrote: > > if this is an idiotic question, i'll blame it on the fact that > there's only decaf left in the house. > > from drivers/spi/spi_stmp.c: > > #define busy_wait(cond) \ > ({ \ > unsigned long end_jiffies = jiffies + STMP_SPI_TIMEOUT; \ > bool succeeded = false; \ > do { \ > if (cond) { \ > succeeded = true; \ > break; \ > } \ > cpu_relax(); \ > } while (time_before(end_jiffies, jiffies)); \ > succeeded; \ > }) > > > is it just me, or do those arguments to time_before() look > backwards? with a quick grep, i found one other example that looks reversed. from drivers/char/hvsi.c: static void hvsi_drain_input(struct hvsi_struct *hp) { uint8_t buf[HVSI_MAX_READ] __ALIGNED__; unsigned long end_jiffies = jiffies + HVSI_TIMEOUT; while (time_before(end_jiffies, jiffies)) if (0 == hvsi_read(hp, buf, HVSI_MAX_READ)) break; } surely that's backwards as well, no? rday -- ======================================================================== Robert P. J. Day Waterloo, Ontario, CANADA Linux Consulting, Training and Kernel Pedantry. Web page: http://crashcourse.ca Twitter: http://twitter.com/rpjday ======================================================================== -- 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/