From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755772AbdLVBIF (ORCPT ); Thu, 21 Dec 2017 20:08:05 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:35681 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755562AbdLVBIC (ORCPT ); Thu, 21 Dec 2017 20:08:02 -0500 Date: Thu, 21 Dec 2017 17:07:59 -0800 From: Matthew Wilcox To: Ross Zwisler Cc: linux-kernel@vger.kernel.org, Dave Hansen , linux-mm@kvack.org, Josh Triplett , Matthew Wilcox Subject: Re: [PATCH 1/2] mm: Make follow_pte_pmd an inline Message-ID: <20171222010759.GA23624@bombadil.infradead.org> References: <20171219165823.24243-1-willy@infradead.org> <20171221212943.GB9087@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171221212943.GB9087@linux.intel.com> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 21, 2017 at 02:29:43PM -0700, Ross Zwisler wrote: > On Tue, Dec 19, 2017 at 08:58:22AM -0800, Matthew Wilcox wrote: > > From: Matthew Wilcox > > > > The one user of follow_pte_pmd (dax) emits a sparse warning because > > it doesn't know that follow_pte_pmd conditionally returns with the > > pte/pmd locked. The required annotation is already there; it's just > > in the wrong file. > > Can you help me find the required annotation that is already there but in the > wrong file? You cut it out ... that was the entire contents of the patch! The cond_lock annotation is correct, but sparse doesn't look across compilation units, so it can't see the one that's in mm/memory.c when it's compiling fs/dax.c. That's why it needs to be in a header file. > This does seem to quiet a lockep warning in fs/dax.c, but I think we still > have a related one in mm/memory.c: > > mm/memory.c:4204:5: warning: context imbalance in '__follow_pte_pmd' - different lock contexts for basic block > > Should we deal with this one as well? I'm not sure how to deal with that one, to be honest.