Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753159AbcLEXEL convert rfc822-to-8bit (ORCPT ); Mon, 5 Dec 2016 18:04:11 -0500 Received: from mga14.intel.com ([192.55.52.115]:20510 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751590AbcLEXEI (ORCPT ); Mon, 5 Dec 2016 18:04:08 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,749,1477983600"; d="scan'208";a="39088580" Subject: Re: [PATCH 04/22] staging: lustre: osc: handle osc eviction correctly Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: text/plain; charset=us-ascii From: Oleg Drokin In-Reply-To: <20161205205537.GB31465@mwanda> Date: Mon, 5 Dec 2016 18:03:58 -0500 Cc: James Simmons , Greg Kroah-Hartman , , Andreas Dilger , Linux Kernel Mailing List , Jinshan Xiong , Lustre Development List Content-Transfer-Encoding: 8BIT Message-Id: References: <1480726409-20350-1-git-send-email-jsimmons@infradead.org> <1480726409-20350-5-git-send-email-jsimmons@infradead.org> <20161205205537.GB31465@mwanda> To: Dan Carpenter X-Mailer: Apple Mail (2.1283) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1134 Lines: 27 On Dec 5, 2016, at 3:55 PM, Dan Carpenter wrote: > On Fri, Dec 02, 2016 at 07:53:11PM -0500, James Simmons wrote: >> @@ -3183,8 +3182,10 @@ static int discard_cb(const struct lu_env *env, struct cl_io *io, >> /* page is top page. */ >> info->oti_next_index = osc_index(ops) + 1; >> if (cl_page_own(env, io, page) == 0) { >> - KLASSERT(ergo(page->cp_type == CPT_CACHEABLE, >> - !PageDirty(cl_page_vmpage(page)))); >> + if (!ergo(page->cp_type == CPT_CACHEABLE, >> + !PageDirty(cl_page_vmpage(page)))) >> + CL_PAGE_DEBUG(D_ERROR, env, page, >> + "discard dirty page?\n"); > > > I don't understand the point of the ergo macro. There are way too many > double negatives (some of them hidden for my small brain). How is that > simpler than just writing it out: > > if (page->cp_type == CPT_CACHEABLE && > PageDirty(cl_page_vmpage(page)) > CL_PAGE_DEBUG(D_ERROR, env, page, "discard dirty page?\n"); I guess it makes it sound chic or something? I am not a huge fan of it either, esp. in a case like this, though it might be somewhat more convenient in assertions (where this is converted from).