From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Schwab Date: Fri, 16 Feb 2007 16:43:32 +0000 Subject: Re: [KJ] [PATCH] is_power_of_2 in ia64mm Message-Id: List-Id: References: <1171627435.6127.0.camel@wriver-t81fb058.linuxcoe> <45D5C789.1090607@student.ltu.se> <45D5D47F.3000303@student.ltu.se> <45D5DE6F.6030604@student.ltu.se> In-Reply-To: <45D5DE6F.6030604@student.ltu.se> (Richard Knutsson's message of "Fri, 16 Feb 2007 17:40:15 +0100") MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable 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 Richard Knutsson writes: > Andreas Schwab wrote: >> Richard Knutsson writes: >> =20 >>> Andreas Schwab wrote: >>> =20 >>>> Richard Knutsson writes: >>>> =20 >>>>> Vignesh Babu BM wrote: >>>>> =20 >>>>>> @@ -175,7 +176,7 @@ static int __init hugetlb_setup_sz(char *str) >>>>>> tr_pages =3D 0x15557000UL; >>>>>> size =3D memparse(str, &str); >>>>>> - if (*str || (size & (size-1)) || !(tr_pages & size) || >>>>>> + if (*str || !is_power_of_2(size) || !(tr_pages & size) || >>>>>> size <=3D PAGE_SIZE || >>>>>> size >=3D (1UL << PAGE_SHIFT << MAX_ORDER)) { >>>>>> printk(KERN_WARNING "Invalid huge page size specified\n"); >>>>>> =20 >>>>> As we talked about before; is this really correct? !is_power_of_2(0) = =3D >>>>> true while (0 & (0-1)) =3D 0. >>>>> =20 >>>> size =3D 0 is also covered by the next two conditions, so the overall = value >>>> does not change. >>>> =20 >>> Yes, but is it meant to state that 'size' is not a power of two? >>> =20 >> >> What else can it mean? >> =20 > What about !one_or_less_bit()? Obviously not. Andreas. --=20 Andreas Schwab, SuSE Labs, schwab@suse.de SuSE Linux Products GmbH, Maxfeldstra=DFe 5, 90409 N=FCrnberg, Germany PGP key fingerprint =3D 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different."