From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A4C8C2D0DB for ; Tue, 28 Jan 2020 16:16:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 550F0214AF for ; Tue, 28 Jan 2020 16:16:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726166AbgA1QQ5 (ORCPT ); Tue, 28 Jan 2020 11:16:57 -0500 Received: from mx2.suse.de ([195.135.220.15]:49890 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726007AbgA1QQ5 (ORCPT ); Tue, 28 Jan 2020 11:16:57 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id BD70FAC92; Tue, 28 Jan 2020 16:16:55 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 62D16DA730; Tue, 28 Jan 2020 17:16:37 +0100 (CET) Date: Tue, 28 Jan 2020 17:16:37 +0100 From: David Sterba To: Josef Bacik Cc: fdmanana@kernel.org, linux-btrfs@vger.kernel.org Subject: Re: [PATCH 2/2] Btrfs: don't iterate mod seq list when putting a tree mod seq Message-ID: <20200128161637.GV3929@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Josef Bacik , fdmanana@kernel.org, linux-btrfs@vger.kernel.org References: <20200122122354.30132-1-fdmanana@kernel.org> <0e0ebc11-e0e1-c283-3e71-881ba78ed3bf@toxicpanda.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0e0ebc11-e0e1-c283-3e71-881ba78ed3bf@toxicpanda.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Wed, Jan 22, 2020 at 03:32:16PM -0500, Josef Bacik wrote: > On 1/22/20 7:23 AM, fdmanana@kernel.org wrote: > > From: Filipe Manana > > > > Each new element added to the mod seq list is always appended to the list, > > and each one gets a sequence number coming from a counter which gets > > incremented everytime a new element is added to the list (or a new node > > is added to the tree mod log rbtree). Therefore the element with the > > lowest sequence number is always the first element in the list. > > > > So just remove the list iteration at btrfs_put_tree_mod_seq() that > > computes the minimum sequence number in the list and replace it with > > a check for the first element's sequence number. > > > > Signed-off-by: Filipe Manana > > This looks like a prime place for list_first_entry_or_null, but I'm not married > to it The if (!list_empty()) looks more readable to me as it's explicit, only implied by list_first_entry_or_null.