Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946007AbXBPQno (ORCPT ); Fri, 16 Feb 2007 11:43:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946004AbXBPQnn (ORCPT ); Fri, 16 Feb 2007 11:43:43 -0500 Received: from cantor.suse.de ([195.135.220.2]:45278 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946003AbXBPQnm (ORCPT ); Fri, 16 Feb 2007 11:43:42 -0500 From: Andreas Schwab To: Richard Knutsson Cc: Vignesh Babu BM , Kernel Janitors List , linux-mm@kvack.org, tony.luck@intel.com, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [KJ] [PATCH] is_power_of_2 in ia64mm References: <1171627435.6127.0.camel@wriver-t81fb058.linuxcoe> <45D5C789.1090607@student.ltu.se> <45D5D47F.3000303@student.ltu.se> <45D5DE6F.6030604@student.ltu.se> X-Yow: Here is my refrigerator full of FLANK STEAK...and over there is my UPHOLSTERED CANOE...I don't know WHY I OWN them!! Date: Fri, 16 Feb 2007 17:43:32 +0100 In-Reply-To: <45D5DE6F.6030604@student.ltu.se> (Richard Knutsson's message of "Fri, 16 Feb 2007 17:40:15 +0100") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/22.0.91 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1625 Lines: 47 Richard Knutsson writes: > Andreas Schwab wrote: >> Richard Knutsson writes: >> >>> Andreas Schwab wrote: >>> >>>> Richard Knutsson writes: >>>> >>>>> Vignesh Babu BM wrote: >>>>> >>>>>> @@ -175,7 +176,7 @@ static int __init hugetlb_setup_sz(char *str) >>>>>> tr_pages = 0x15557000UL; >>>>>> size = memparse(str, &str); >>>>>> - if (*str || (size & (size-1)) || !(tr_pages & size) || >>>>>> + if (*str || !is_power_of_2(size) || !(tr_pages & size) || >>>>>> size <= PAGE_SIZE || >>>>>> size >= (1UL << PAGE_SHIFT << MAX_ORDER)) { >>>>>> printk(KERN_WARNING "Invalid huge page size specified\n"); >>>>>> >>>>> As we talked about before; is this really correct? !is_power_of_2(0) == >>>>> true while (0 & (0-1)) == 0. >>>>> >>>> size == 0 is also covered by the next two conditions, so the overall value >>>> does not change. >>>> >>> Yes, but is it meant to state that 'size' is not a power of two? >>> >> >> What else can it mean? >> > What about !one_or_less_bit()? Obviously not. Andreas. -- Andreas Schwab, SuSE Labs, schwab@suse.de SuSE Linux Products GmbH, Maxfeldstra?e 5, 90409 N?rnberg, Germany PGP key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different." - 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/