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Mon, 18 Apr 2022 15:09:39 -0700 (PDT) Message-ID: <1d9a2146-9e48-ba97-d049-5d2332ebbd3a@arm.com> Date: Mon, 18 Apr 2022 23:09:36 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH 02/13] iommu: Move bus setup to IOMMU device registration Content-Language: en-GB To: Lu Baolu , joro@8bytes.org, will@kernel.org References: From: Robin Murphy In-Reply-To: Cc: jean-philippe@linaro.org, zhang.lyra@gmail.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, thierry.reding@gmail.com, linux-arm-kernel@lists.infradead.org, gerald.schaefer@linux.ibm.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" T24gMjAyMi0wNC0xNiAwMTowNCwgTHUgQmFvbHUgd3JvdGU6Cj4gT24gMjAyMi80LzE0IDIwOjQy LCBSb2JpbiBNdXJwaHkgd3JvdGU6Cj4+IEBAIC0xODgzLDI3ICsxOTAwLDEyIEBAIHN0YXRpYyBp bnQgaW9tbXVfYnVzX2luaXQoc3RydWN0IGJ1c190eXBlICpidXMpCj4+IMKgwqAgKi8KPj4gwqAg aW50IGJ1c19zZXRfaW9tbXUoc3RydWN0IGJ1c190eXBlICpidXMsIGNvbnN0IHN0cnVjdCBpb21t dV9vcHMgKm9wcykKPj4gwqAgewo+PiAtwqDCoMKgIGludCBlcnI7Cj4+IC0KPj4gLcKgwqDCoCBp ZiAob3BzID09IE5VTEwpIHsKPj4gLcKgwqDCoMKgwqDCoMKgIGJ1cy0+aW9tbXVfb3BzID0gTlVM TDsKPj4gLcKgwqDCoMKgwqDCoMKgIHJldHVybiAwOwo+PiAtwqDCoMKgIH0KPj4gLQo+PiAtwqDC oMKgIGlmIChidXMtPmlvbW11X29wcyAhPSBOVUxMKQo+PiArwqDCoMKgIGlmIChidXMtPmlvbW11 X29wcyAmJiBvcHMgJiYgYnVzLT5pb21tdV9vcHMgIT0gb3BzKQo+PiDCoMKgwqDCoMKgwqDCoMKg wqAgcmV0dXJuIC1FQlVTWTsKPj4gwqDCoMKgwqDCoCBidXMtPmlvbW11X29wcyA9IG9wczsKPiAK PiBEbyB3ZSBzdGlsbCBuZWVkIHRvIGtlZXAgYWJvdmUgbGluZXMgaW4gYnVzX3NldF9pb21tdSgp PwoKSXQgcHJlc2VydmVzIHRoZSBleGlzdGluZyBiZWhhdmlvdXIgdW50aWwgZWFjaCBjYWxsc2l0 ZSBhbmQgaXRzIAphc3NvY2lhdGVkIGVycm9yIGhhbmRsaW5nIGFyZSByZW1vdmVkIGxhdGVyIG9u LCB3aGljaCBzZWVtcyBsaWtlIGFzIGdvb2QgCmEgdGhpbmcgdG8gZG8gYXMgYW55LiBTaW5jZSBJ J20gYWxyZWFkeSByZWxheGluZyBpb21tdV9kZXZpY2VfcmVnaXN0ZXIoKSAKdG8gYSB3YXJuLWJ1 dC1jb250aW51ZSBiZWhhdmlvdXIgd2hpbGUgaXQga2VlcHMgdGhlIGJ1cyBvcHMgb24gCmxpZmUt c3VwcG9ydCBpbnRlcm5hbGx5LCBJIGZpZ3VyZWQgbm90IGNoYW5naW5nIHRvbyBtdWNoIGF0IG9u Y2Ugd291bGQgCm1ha2UgaXQgZWFzaWVyIHRvIGJpc2VjdCBhbnkgcG90ZW50aWFsIGlzc3VlcyBh cmlzaW5nIGZyb20gdGhpcyBmaXJzdCBzdGVwLgoKVGhhbmtzLApSb2Jpbi4KX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KaW9tbXUgbWFpbGluZyBsaXN0Cmlv bW11QGxpc3RzLmxpbnV4LWZvdW5kYXRpb24ub3JnCmh0dHBzOi8vbGlzdHMubGludXhmb3VuZGF0 aW9uLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2lvbW11 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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B30BC433F5 for ; Mon, 18 Apr 2022 22:10:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230446AbiDRWMw (ORCPT ); Mon, 18 Apr 2022 18:12:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230386AbiDRWMc (ORCPT ); Mon, 18 Apr 2022 18:12:32 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 71CB320F43 for ; Mon, 18 Apr 2022 15:09:43 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CD81D1042; Mon, 18 Apr 2022 15:09:42 -0700 (PDT) Received: from [10.57.41.251] (unknown [10.57.41.251]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A92383F766; Mon, 18 Apr 2022 15:09:39 -0700 (PDT) Message-ID: <1d9a2146-9e48-ba97-d049-5d2332ebbd3a@arm.com> Date: Mon, 18 Apr 2022 23:09:36 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH 02/13] iommu: Move bus setup to IOMMU device registration Content-Language: en-GB To: Lu Baolu , joro@8bytes.org, will@kernel.org Cc: iommu@lists.linux-foundation.org, sven@svenpeter.dev, robdclark@gmail.com, m.szyprowski@samsung.com, yong.wu@mediatek.com, mjrosato@linux.ibm.com, gerald.schaefer@linux.ibm.com, zhang.lyra@gmail.com, thierry.reding@gmail.com, vdumpa@nvidia.com, jean-philippe@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: From: Robin Murphy In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022-04-16 01:04, Lu Baolu wrote: > On 2022/4/14 20:42, Robin Murphy wrote: >> @@ -1883,27 +1900,12 @@ static int iommu_bus_init(struct bus_type *bus) >>    */ >>   int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops) >>   { >> -    int err; >> - >> -    if (ops == NULL) { >> -        bus->iommu_ops = NULL; >> -        return 0; >> -    } >> - >> -    if (bus->iommu_ops != NULL) >> +    if (bus->iommu_ops && ops && bus->iommu_ops != ops) >>           return -EBUSY; >>       bus->iommu_ops = ops; > > Do we still need to keep above lines in bus_set_iommu()? It preserves the existing behaviour until each callsite and its associated error handling are removed later on, which seems like as good a thing to do as any. Since I'm already relaxing iommu_device_register() to a warn-but-continue behaviour while it keeps the bus ops on life-support internally, I figured not changing too much at once would make it easier to bisect any potential issues arising from this first step. Thanks, Robin. 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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BCEACC433F5 for ; Mon, 18 Apr 2022 22:10:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:To:Subject:MIME-Version: Date:Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=wFLGFeIn814BzKvoVMEIPiGMb86EUEymseCTieIEIGA=; b=LwlCHYSCfL+q7KMCfjLgpI/m1Z eyUSwVEN/rSH7CSruMF4EBurYb87QiB1dDxL3fVAphs7d44o82zpYabqJiC2aFWpNLNJkN/pBTMpC fsAuZu+Rc9+aP5rQeAyB6OXKAmQiPSMM9wOEGkvxxR99H8BjhCBbsuhW2tHerNOQYydgZJRxjrxbc fxTcGETi+3Z4XryZ3Ewp9O0y460gXdxnS1BEXRtZDhUgDj73zkK57eEM0qz58YLBy2mA7Gc+L3YnB 11vJTPCYeBrg/QzouWbNhFp/NWJIKD0v4sgCUhmADKEbvzE59T3o39/7KwuzV5OrpHatUjFt3ppU+ pUNIFmzQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngZZ8-000h9C-4y; Mon, 18 Apr 2022 22:09:50 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngZZ4-000h7W-Os for linux-arm-kernel@lists.infradead.org; Mon, 18 Apr 2022 22:09:48 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CD81D1042; Mon, 18 Apr 2022 15:09:42 -0700 (PDT) Received: from [10.57.41.251] (unknown [10.57.41.251]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A92383F766; Mon, 18 Apr 2022 15:09:39 -0700 (PDT) Message-ID: <1d9a2146-9e48-ba97-d049-5d2332ebbd3a@arm.com> Date: Mon, 18 Apr 2022 23:09:36 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH 02/13] iommu: Move bus setup to IOMMU device registration Content-Language: en-GB To: Lu Baolu , joro@8bytes.org, will@kernel.org References: From: Robin Murphy In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220418_150946_890466_577C5957 X-CRM114-Status: GOOD ( 10.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: jean-philippe@linaro.org, mjrosato@linux.ibm.com, sven@svenpeter.dev, zhang.lyra@gmail.com, robdclark@gmail.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, thierry.reding@gmail.com, linux-arm-kernel@lists.infradead.org, gerald.schaefer@linux.ibm.com, yong.wu@mediatek.com, m.szyprowski@samsung.com Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gMjAyMi0wNC0xNiAwMTowNCwgTHUgQmFvbHUgd3JvdGU6Cj4gT24gMjAyMi80LzE0IDIwOjQy LCBSb2JpbiBNdXJwaHkgd3JvdGU6Cj4+IEBAIC0xODgzLDI3ICsxOTAwLDEyIEBAIHN0YXRpYyBp bnQgaW9tbXVfYnVzX2luaXQoc3RydWN0IGJ1c190eXBlICpidXMpCj4+IMKgwqAgKi8KPj4gwqAg aW50IGJ1c19zZXRfaW9tbXUoc3RydWN0IGJ1c190eXBlICpidXMsIGNvbnN0IHN0cnVjdCBpb21t dV9vcHMgKm9wcykKPj4gwqAgewo+PiAtwqDCoMKgIGludCBlcnI7Cj4+IC0KPj4gLcKgwqDCoCBp ZiAob3BzID09IE5VTEwpIHsKPj4gLcKgwqDCoMKgwqDCoMKgIGJ1cy0+aW9tbXVfb3BzID0gTlVM TDsKPj4gLcKgwqDCoMKgwqDCoMKgIHJldHVybiAwOwo+PiAtwqDCoMKgIH0KPj4gLQo+PiAtwqDC oMKgIGlmIChidXMtPmlvbW11X29wcyAhPSBOVUxMKQo+PiArwqDCoMKgIGlmIChidXMtPmlvbW11 X29wcyAmJiBvcHMgJiYgYnVzLT5pb21tdV9vcHMgIT0gb3BzKQo+PiDCoMKgwqDCoMKgwqDCoMKg wqAgcmV0dXJuIC1FQlVTWTsKPj4gwqDCoMKgwqDCoCBidXMtPmlvbW11X29wcyA9IG9wczsKPiAK PiBEbyB3ZSBzdGlsbCBuZWVkIHRvIGtlZXAgYWJvdmUgbGluZXMgaW4gYnVzX3NldF9pb21tdSgp PwoKSXQgcHJlc2VydmVzIHRoZSBleGlzdGluZyBiZWhhdmlvdXIgdW50aWwgZWFjaCBjYWxsc2l0 ZSBhbmQgaXRzIAphc3NvY2lhdGVkIGVycm9yIGhhbmRsaW5nIGFyZSByZW1vdmVkIGxhdGVyIG9u LCB3aGljaCBzZWVtcyBsaWtlIGFzIGdvb2QgCmEgdGhpbmcgdG8gZG8gYXMgYW55LiBTaW5jZSBJ J20gYWxyZWFkeSByZWxheGluZyBpb21tdV9kZXZpY2VfcmVnaXN0ZXIoKSAKdG8gYSB3YXJuLWJ1 dC1jb250aW51ZSBiZWhhdmlvdXIgd2hpbGUgaXQga2VlcHMgdGhlIGJ1cyBvcHMgb24gCmxpZmUt c3VwcG9ydCBpbnRlcm5hbGx5LCBJIGZpZ3VyZWQgbm90IGNoYW5naW5nIHRvbyBtdWNoIGF0IG9u Y2Ugd291bGQgCm1ha2UgaXQgZWFzaWVyIHRvIGJpc2VjdCBhbnkgcG90ZW50aWFsIGlzc3VlcyBh cmlzaW5nIGZyb20gdGhpcyBmaXJzdCBzdGVwLgoKVGhhbmtzLApSb2Jpbi4KCl9fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCmxpbnV4LWFybS1rZXJuZWwgbWFp bGluZyBsaXN0CmxpbnV4LWFybS1rZXJuZWxAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlz dHMuaW5mcmFkZWFkLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4LWFybS1rZXJuZWwK