From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751836AbeCWTln (ORCPT ); Fri, 23 Mar 2018 15:41:43 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:42216 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751471AbeCWTll (ORCPT ); Fri, 23 Mar 2018 15:41:41 -0400 Date: Fri, 23 Mar 2018 20:41:37 +0100 (CET) From: Thomas Gleixner To: Konrad Rzeszutek Wilk cc: Christoph Hellwig , mingo@elte.hu, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org Subject: Re: [PATCH] swiotlb: swiotlb_{alloc,free}_buffer should depend on CONFIG_DMA_DIRECT_OPS In-Reply-To: <20180323185707.GD25533@char.us.oracle.com> Message-ID: References: <20180323174930.17767-1-hch@lst.de> <20180323185707.GD25533@char.us.oracle.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 23 Mar 2018, Konrad Rzeszutek Wilk wrote: > On Fri, Mar 23, 2018 at 06:49:30PM +0100, Christoph Hellwig wrote: > > Otherwise we might get unused symbol warnings for configs that built > > swiotlb.c only for use by xen-swiotlb.c and that don't otherwise select > > CONFIG_DMA_DIRECT_OPS, which is possible on arm. > > > > Fixes: 16e73adbca76 ("dma/swiotlb: Remove swiotlb_{alloc,free}_coherent()") > > Reported-by: Stephen Rothwell > > Signed-off-by: Christoph Hellwig > > > Alternatively could we set the Kconfig to slect DMA_DIRECT_OPS? You only want to do that when you actually need the code. If not it's a pointless exercise. But Christoph change makes sense independent of that because the next oddball Kconfig will come along sooner than later and run into the very same problem. Thanks, tglx