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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 0AEC6C43331 for ; Fri, 6 Sep 2019 14:01:31 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DDD4D2070C for ; Fri, 6 Sep 2019 14:01:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DDD4D2070C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id A693A2352; Fri, 6 Sep 2019 14:01:30 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 0655D234A for ; Fri, 6 Sep 2019 14:01:29 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id D9D4C7DB for ; Fri, 6 Sep 2019 14:01:27 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id C476768B05; Fri, 6 Sep 2019 16:01:23 +0200 (CEST) Date: Fri, 6 Sep 2019 16:01:23 +0200 From: Christoph Hellwig To: Boris Ostrovsky Subject: Re: [PATCH 09/11] swiotlb-xen: simplify cache maintainance Message-ID: <20190906140123.GA9894@lst.de> References: <20190905113408.3104-1-hch@lst.de> <20190905113408.3104-10-hch@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Stefano Stabellini , Konrad Rzeszutek Wilk , x86@kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, gross@suse.com, xen-devel@lists.xenproject.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On Fri, Sep 06, 2019 at 09:52:12AM -0400, Boris Ostrovsky wrote: > We need nop definitions of these two for x86. > > Everything builds now but that's probably because the calls are under > 'if (!dev_is_dma_coherent(dev))' which is always false so compiler > optimized is out. I don't think we should rely on that. That is how a lot of the kernel works. Provide protypes only for code that is semantically compiled, but can't ever be called due to IS_ENABLED() checks. It took me a while to get used to it, but it actually is pretty nice as the linker does the work for you to check that it really is never called. Much better than say a BUILD_BUG_ON(). _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu 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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 89837C43331 for ; Fri, 6 Sep 2019 14:02:12 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 664062070C for ; Fri, 6 Sep 2019 14:02:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 664062070C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1i6Enp-0006ah-RB; Fri, 06 Sep 2019 14:01:29 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1i6Eno-0006aW-MK for xen-devel@lists.xenproject.org; Fri, 06 Sep 2019 14:01:28 +0000 X-Inumbo-ID: d10d6e8f-d0ae-11e9-abf6-12813bfff9fa Received: from verein.lst.de (unknown [213.95.11.211]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id d10d6e8f-d0ae-11e9-abf6-12813bfff9fa; Fri, 06 Sep 2019 14:01:27 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id C476768B05; Fri, 6 Sep 2019 16:01:23 +0200 (CEST) Date: Fri, 6 Sep 2019 16:01:23 +0200 From: Christoph Hellwig To: Boris Ostrovsky Message-ID: <20190906140123.GA9894@lst.de> References: <20190905113408.3104-1-hch@lst.de> <20190905113408.3104-10-hch@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Subject: Re: [Xen-devel] [PATCH 09/11] swiotlb-xen: simplify cache maintainance X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Konrad Rzeszutek Wilk , x86@kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, gross@suse.com, xen-devel@lists.xenproject.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" T24gRnJpLCBTZXAgMDYsIDIwMTkgYXQgMDk6NTI6MTJBTSAtMDQwMCwgQm9yaXMgT3N0cm92c2t5 IHdyb3RlOgo+IFdlIG5lZWQgbm9wIGRlZmluaXRpb25zIG9mIHRoZXNlIHR3byBmb3IgeDg2Lgo+ IAo+IEV2ZXJ5dGhpbmcgYnVpbGRzIG5vdyBidXQgdGhhdCdzIHByb2JhYmx5IGJlY2F1c2UgdGhl IGNhbGxzIGFyZSB1bmRlcgo+ICdpZiAoIWRldl9pc19kbWFfY29oZXJlbnQoZGV2KSknIHdoaWNo IGlzIGFsd2F5cyBmYWxzZSBzbyBjb21waWxlcgo+IG9wdGltaXplZCBpcyBvdXQuIEkgZG9uJ3Qg dGhpbmsgd2Ugc2hvdWxkIHJlbHkgb24gdGhhdC4KClRoYXQgaXMgaG93IGEgbG90IG9mIHRoZSBr ZXJuZWwgd29ya3MuICBQcm92aWRlIHByb3R5cGVzIG9ubHkgZm9yIGNvZGUKdGhhdCBpcyBzZW1h bnRpY2FsbHkgY29tcGlsZWQsIGJ1dCBjYW4ndCBldmVyIGJlIGNhbGxlZCBkdWUgdG8KSVNfRU5B QkxFRCgpIGNoZWNrcy4gIEl0IHRvb2sgbWUgYSB3aGlsZSB0byBnZXQgdXNlZCB0byBpdCwgYnV0 IGl0CmFjdHVhbGx5IGlzIHByZXR0eSBuaWNlIGFzIHRoZSBsaW5rZXIgZG9lcyB0aGUgd29yayBm b3IgeW91IHRvIGNoZWNrCnRoYXQgaXQgcmVhbGx5IGlzIG5ldmVyIGNhbGxlZC4gIE11Y2ggYmV0 dGVyIHRoYW4gc2F5IGEgQlVJTERfQlVHX09OKCkuCgpfX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fXwpYZW4tZGV2ZWwgbWFpbGluZyBsaXN0Clhlbi1kZXZlbEBs aXN0cy54ZW5wcm9qZWN0Lm9yZwpodHRwczovL2xpc3RzLnhlbnByb2plY3Qub3JnL21haWxtYW4v bGlzdGluZm8veGVuLWRldmVs 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=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 14E75C43331 for ; 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X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Konrad Rzeszutek Wilk , x86@kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, gross@suse.com, xen-devel@lists.xenproject.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Sep 06, 2019 at 09:52:12AM -0400, Boris Ostrovsky wrote: > We need nop definitions of these two for x86. > > Everything builds now but that's probably because the calls are under > 'if (!dev_is_dma_coherent(dev))' which is always false so compiler > optimized is out. I don't think we should rely on that. That is how a lot of the kernel works. Provide protypes only for code that is semantically compiled, but can't ever be called due to IS_ENABLED() checks. It took me a while to get used to it, but it actually is pretty nice as the linker does the work for you to check that it really is never called. Much better than say a BUILD_BUG_ON(). _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 23517C43331 for ; Fri, 6 Sep 2019 14:01:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0794A2070C for ; Fri, 6 Sep 2019 14:01:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393855AbfIFOB2 (ORCPT ); Fri, 6 Sep 2019 10:01:28 -0400 Received: from verein.lst.de ([213.95.11.211]:57552 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732131AbfIFOB2 (ORCPT ); Fri, 6 Sep 2019 10:01:28 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id C476768B05; Fri, 6 Sep 2019 16:01:23 +0200 (CEST) Date: Fri, 6 Sep 2019 16:01:23 +0200 From: Christoph Hellwig To: Boris Ostrovsky Cc: Christoph Hellwig , Stefano Stabellini , Konrad Rzeszutek Wilk , gross@suse.com, x86@kernel.org, linux-arm-kernel@lists.infradead.org, xen-devel@lists.xenproject.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 09/11] swiotlb-xen: simplify cache maintainance Message-ID: <20190906140123.GA9894@lst.de> References: <20190905113408.3104-1-hch@lst.de> <20190905113408.3104-10-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 06, 2019 at 09:52:12AM -0400, Boris Ostrovsky wrote: > We need nop definitions of these two for x86. > > Everything builds now but that's probably because the calls are under > 'if (!dev_is_dma_coherent(dev))' which is always false so compiler > optimized is out. I don't think we should rely on that. That is how a lot of the kernel works. Provide protypes only for code that is semantically compiled, but can't ever be called due to IS_ENABLED() checks. It took me a while to get used to it, but it actually is pretty nice as the linker does the work for you to check that it really is never called. Much better than say a BUILD_BUG_ON().