From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <45D5C789.1090607@student.ltu.se> Date: Fri, 16 Feb 2007 16:02:33 +0100 From: Richard Knutsson MIME-Version: 1.0 Subject: Re: [KJ] [PATCH] is_power_of_2 in ia64mm References: <1171627435.6127.0.camel@wriver-t81fb058.linuxcoe> In-Reply-To: <1171627435.6127.0.camel@wriver-t81fb058.linuxcoe> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Vignesh Babu BM Cc: Kernel Janitors List , linux-mm@kvack.org, tony.luck@intel.com, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org List-ID: Vignesh Babu BM wrote: > Replacing (n & (n-1)) in the context of power of 2 checks > with is_power_of_2 > > > diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c > index 0c7e94e..0ccc70e 100644 > --- a/arch/ia64/mm/hugetlbpage.c > +++ b/arch/ia64/mm/hugetlbpage.c > @@ -16,6 +16,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -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. Richard Knutsson -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org