From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx105.postini.com [74.125.245.105]) by kanga.kvack.org (Postfix) with SMTP id A8A886B0111 for ; Wed, 28 Mar 2012 13:29:04 -0400 (EDT) Message-ID: <4F6CA298.4000301@jp.fujitsu.com> Date: Fri, 23 Mar 2012 12:19:36 -0400 From: KOSAKI Motohiro MIME-Version: 1.0 Subject: Re: [PATCH 00/16] mm: prepare for converting vm->vm_flags to 64-bit References: <20120321065140.13852.52315.stgit@zurg> <20120321100602.GA5522@barrios> <4F69D496.2040509@openvz.org> <20120322142647.42395398.akpm@linux-foundation.org> <20120322212810.GE6589@ZenIV.linux.org.uk> In-Reply-To: <20120322212810.GE6589@ZenIV.linux.org.uk> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: viro@ZenIV.linux.org.uk Cc: akpm@linux-foundation.org, khlebnikov@openvz.org, minchan@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, hughd@google.com, kosaki.motohiro@jp.fujitsu.com, benh@kernel.crashing.org, linux@arm.linux.org.uk On 3/22/2012 5:28 PM, Al Viro wrote: > On Thu, Mar 22, 2012 at 02:26:47PM -0700, Andrew Morton wrote: >> It would be nice to find some way of triggering compiler warnings or >> sparse warnings if someone mixes a 32-bit type with a vm_flags_t. Any >> thoughts on this? >> >> (Maybe that's what __nocast does, but Documentation/sparse.txt doesn't >> describe it) > > Use __bitwise for that - check how gfp_t is handled. Hmm.. If now we activate __bitwise, really plenty driver start create lots warnings. Does it make sense? In fact, x86-32 keep 32bit vma_t forever. thus all x86 specific driver don't need any change. Moreover many ancient drivers has no maintainer and I can't expect such driver will be fixed even though a warning occur. So, I think __nocast weakness is better than strict __bitwise annotation for this situation. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org