Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753377AbYCLJt5 (ORCPT ); Wed, 12 Mar 2008 05:49:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752536AbYCLJtf (ORCPT ); Wed, 12 Mar 2008 05:49:35 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:59482 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752488AbYCLJte (ORCPT ); Wed, 12 Mar 2008 05:49:34 -0400 Subject: Re: Q: (stupid) can't we "fix" hlist_for_each_entry() ? From: Peter Zijlstra To: Oleg Nesterov Cc: Andrew Morton , Christoph Hellwig , "Paul E. McKenney" , linux-kernel@vger.kernel.org In-Reply-To: <20080312081201.GA278@tv-sign.ru> References: <20080312081201.GA278@tv-sign.ru> Content-Type: text/plain Date: Wed, 12 Mar 2008 10:48:50 +0100 Message-Id: <1205315331.8514.225.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.21.92 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1404 Lines: 34 On Wed, 2008-03-12 at 11:12 +0300, Oleg Nesterov wrote: > hlist_for_each_entry/hlist_for_each_entry_rcu doesn't actually need 4 > arguments, it could be > > #define hlist_for_each_entry_rcu(pos, head, member) \ > for (pos = hlist_entry((head)->first, typeof(*(pos)), member); \ > rcu_dereference(pos) != hlist_entry(NULL, typeof(*(pos)), member) && \ > ({ prefetch((pos)->member.next); 1; }); \ > (pos) = hlist_entry((pos)->member.next, typeof(*(pos)), member)) > > Or, > > #define hlist_for_each_entry_rcu(pos, head, member) \ > for (pos = (void*)(head)->first; \ > rcu_dereference(pos) && ({ prefetch(((hlist_node*)pos)->next); 1; }) && \ > ({ (pos) = hlist_entry((void*)(pos), typeof(*(pos)), member)); 1; }); \ > (pos) = (void*)(pos)->member.next) > > Q: is it worth "fixing" ? I'm in favour. > If yes, what is the "right" way to do this? These macros are spread all over > the kernel... The usual way would be to prepare a git tree for Linus to pull right after -rc1 I think was the best point, and at the same time supply Andrew with a bunch of patches fixing up the various users in his tree. -- 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/