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 2ED74C433EF for ; Tue, 22 Feb 2022 08:37:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229540AbiBVIhk (ORCPT ); Tue, 22 Feb 2022 03:37:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229515AbiBVIhj (ORCPT ); Tue, 22 Feb 2022 03:37:39 -0500 Received: from mail.kapsi.fi (mail.kapsi.fi [IPv6:2001:67c:1be8::25]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2483C8F61E; Tue, 22 Feb 2022 00:37:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=kapsi.fi; s=20161220; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=7Y5Q0bIv6KCJJMw/T06DdwsQiFx+TO703WYBc0RO2zg=; b=1BASgC2ZmAp7Yuf1iRh/CZrpM+ fUes0bn2kS7zkMDCz1SLhO7N2+FCpEpAiKn1Y3+EZMMlwpwQ7R7NKXAtcCaom+H6pkDtZWlW+wIx/ 8hnwMmQ+V4dv//mER9Yle4tcbymSC3T5g6HMT7YDP0pzHTb1rEQsuTX0nosAUfeIn5lJe9hHKKvwP gbcThs7e1pUbiiiK+Ye8R9KPzRr9nggO5p5zj1XuaZIiSuXK3c662c0q+M02SlRwvTranKvMD6sQg 4LKm0IlHl2rJElKURPmgu6a80acIsyj3EnNIVWxgkO1mETmOJBImYmwsQDTT6qReeeXHHXyYZegpV 81lXv4Pg==; Received: from 91-158-25-70.elisa-laajakaista.fi ([91.158.25.70] helo=[192.168.1.10]) by mail.kapsi.fi with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1nMQfS-00063Y-Iy; Tue, 22 Feb 2022 10:37:06 +0200 Message-ID: <134c4a28-4331-deed-a374-75c9711168f0@kapsi.fi> Date: Tue, 22 Feb 2022 10:37:05 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [PATCH v3 9/9] drm/tegra: Support context isolation Content-Language: en-US To: Dmitry Osipenko , Mikko Perttunen , thierry.reding@gmail.com, jonathanh@nvidia.com, joro@8bytes.org, will@kernel.org, robh+dt@kernel.org, robin.murphy@arm.com Cc: linux-tegra@vger.kernel.org, dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20220218113952.3077606-1-mperttunen@nvidia.com> <20220218113952.3077606-10-mperttunen@nvidia.com> <2b4dd244-f918-4d26-2322-00a0bb226ccf@gmail.com> From: Mikko Perttunen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 91.158.25.70 X-SA-Exim-Mail-From: cyndis@kapsi.fi X-SA-Exim-Scanned: No (on mail.kapsi.fi); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org On 2/21/22 22:02, Dmitry Osipenko wrote: > 21.02.2022 15:06, Mikko Perttunen пишет: >> On 2/19/22 20:35, Dmitry Osipenko wrote: >>> 18.02.2022 14:39, Mikko Perttunen пишет: >>>> +    if (context->memory_context && >>>> context->client->ops->get_streamid_offset) { >>>              ^^^ >>>> +        int offset = >>>> context->client->ops->get_streamid_offset(context->client); >>>> + >>>> +        if (offset >= 0) { >>>> +            job->context = context->memory_context; >>>> +            job->engine_streamid_offset = offset; >>>> +            host1x_context_get(job->context); >>>> +        } >>> >>> You should bump refcount unconditionally or you'll get refcnt underflow >>> on put, when offset < 0. >> >> This refcount is intended to be dropped from 'release_job', where it's >> dropped if job->context is set, which it is from this path. >> >>> >>>> +    } >>>> + >>>>       /* >>>>        * job_data is now part of job reference counting, so don't >>>> release >>>>        * it from here. >>>> diff --git a/drivers/gpu/drm/tegra/uapi.c b/drivers/gpu/drm/tegra/uapi.c >>>> index 9ab9179d2026..be33da54d12c 100644 >>>> --- a/drivers/gpu/drm/tegra/uapi.c >>>> +++ b/drivers/gpu/drm/tegra/uapi.c >>>> @@ -33,6 +33,9 @@ static void tegra_drm_channel_context_close(struct >>>> tegra_drm_context *context) >>>>       struct tegra_drm_mapping *mapping; >>>>       unsigned long id; >>>>   +    if (context->memory_context) >>>> +        host1x_context_put(context->memory_context); >>> >>> The "if (context->memory_context && >>> context->client->ops->get_streamid_offset)" above doesn't match the "if >>> (context->memory_context)". You'll get refcount underflow. >> >> And this drop is for the refcount implicitly added when allocating the >> memory context through host1x_context_alloc; so these two places should >> be independent. >> >> Please elaborate if I missed something. > > You named context as memory_context and then have > context=context->memory_context. Please try to improve the variable > names, like drm_ctx->host1x_ctx for example. > > I'm also not a big fan of the "if (ref) put(ref)" pattern. Won't be > better to move all the "if (!NULL)" checks inside of get()/put() and > make the invocations unconditional? I agree that the naming here is confusing with different kinds of contexts flying around, though I would prefer not to change the original 'struct tegra_drm_context *context' since it's used all around the code. But I'll try to make it clearer. Regarding moving NULL checks inside get/put, I personally dislike that pattern (also with e.g. kfree) since when reading the code, it makes it more difficult to see that the pointer can be NULL. Mikko 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 smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 033D6C433F5 for ; Tue, 22 Feb 2022 08:37:20 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 93AA060EA6; Tue, 22 Feb 2022 08:37:20 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id TcfPiEI3vL_v; Tue, 22 Feb 2022 08:37:19 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp3.osuosl.org (Postfix) with ESMTPS id 4CEAF60E93; Tue, 22 Feb 2022 08:37:19 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 20A6CC001A; 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Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [PATCH v3 9/9] drm/tegra: Support context isolation Content-Language: en-US To: Dmitry Osipenko , Mikko Perttunen , thierry.reding@gmail.com, jonathanh@nvidia.com, joro@8bytes.org, will@kernel.org, robh+dt@kernel.org, robin.murphy@arm.com References: <20220218113952.3077606-1-mperttunen@nvidia.com> <20220218113952.3077606-10-mperttunen@nvidia.com> <2b4dd244-f918-4d26-2322-00a0bb226ccf@gmail.com> From: Mikko Perttunen In-Reply-To: X-SA-Exim-Connect-IP: 91.158.25.70 X-SA-Exim-Mail-From: cyndis@kapsi.fi X-SA-Exim-Scanned: No (on mail.kapsi.fi); SAEximRunCond expanded to false Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linux-tegra@vger.kernel.org, linux-arm-kernel@lists.infradead.org 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" T24gMi8yMS8yMiAyMjowMiwgRG1pdHJ5IE9zaXBlbmtvIHdyb3RlOgo+IDIxLjAyLjIwMjIgMTU6 MDYsIE1pa2tvIFBlcnR0dW5lbiDQv9C40YjQtdGCOgo+PiBPbiAyLzE5LzIyIDIwOjM1LCBEbWl0 cnkgT3NpcGVua28gd3JvdGU6Cj4+PiAxOC4wMi4yMDIyIDE0OjM5LCBNaWtrbyBQZXJ0dHVuZW4g 0L/QuNGI0LXRgjoKPj4+PiArwqDCoMKgIGlmIChjb250ZXh0LT5tZW1vcnlfY29udGV4dCAmJgo+ Pj4+IGNvbnRleHQtPmNsaWVudC0+b3BzLT5nZXRfc3RyZWFtaWRfb2Zmc2V0KSB7Cj4+PiAgwqDC oMKgwqDCoMKgwqDCoMKgwqDCoMKgIF5eXgo+Pj4+ICvCoMKgwqDCoMKgwqDCoCBpbnQgb2Zmc2V0 ID0KPj4+PiBjb250ZXh0LT5jbGllbnQtPm9wcy0+Z2V0X3N0cmVhbWlkX29mZnNldChjb250ZXh0 LT5jbGllbnQpOwo+Pj4+ICsKPj4+PiArwqDCoMKgwqDCoMKgwqAgaWYgKG9mZnNldCA+PSAwKSB7 Cj4+Pj4gK8KgwqDCoMKgwqDCoMKgwqDCoMKgwqAgam9iLT5jb250ZXh0ID0gY29udGV4dC0+bWVt b3J5X2NvbnRleHQ7Cj4+Pj4gK8KgwqDCoMKgwqDCoMKgwqDCoMKgwqAgam9iLT5lbmdpbmVfc3Ry ZWFtaWRfb2Zmc2V0ID0gb2Zmc2V0Owo+Pj4+ICvCoMKgwqDCoMKgwqDCoMKgwqDCoMKgIGhvc3Qx eF9jb250ZXh0X2dldChqb2ItPmNvbnRleHQpOwo+Pj4+ICvCoMKgwqDCoMKgwqDCoCB9Cj4+Pgo+ Pj4gWW91IHNob3VsZCBidW1wIHJlZmNvdW50IHVuY29uZGl0aW9uYWxseSBvciB5b3UnbGwgZ2V0 IHJlZmNudCB1bmRlcmZsb3cKPj4+IG9uIHB1dCwgd2hlbiBvZmZzZXQgPCAwLgo+Pgo+PiBUaGlz IHJlZmNvdW50IGlzIGludGVuZGVkIHRvIGJlIGRyb3BwZWQgZnJvbSAncmVsZWFzZV9qb2InLCB3 aGVyZSBpdCdzCj4+IGRyb3BwZWQgaWYgam9iLT5jb250ZXh0IGlzIHNldCwgd2hpY2ggaXQgaXMg ZnJvbSB0aGlzIHBhdGguCj4+Cj4+Pgo+Pj4+ICvCoMKgwqAgfQo+Pj4+ICsKPj4+PiAgwqDCoMKg wqDCoCAvKgo+Pj4+ICDCoMKgwqDCoMKgwqAgKiBqb2JfZGF0YSBpcyBub3cgcGFydCBvZiBqb2Ig cmVmZXJlbmNlIGNvdW50aW5nLCBzbyBkb24ndAo+Pj4+IHJlbGVhc2UKPj4+PiAgwqDCoMKgwqDC oMKgICogaXQgZnJvbSBoZXJlLgo+Pj4+IGRpZmYgLS1naXQgYS9kcml2ZXJzL2dwdS9kcm0vdGVn cmEvdWFwaS5jIGIvZHJpdmVycy9ncHUvZHJtL3RlZ3JhL3VhcGkuYwo+Pj4+IGluZGV4IDlhYjkx NzlkMjAyNi4uYmUzM2RhNTRkMTJjIDEwMDY0NAo+Pj4+IC0tLSBhL2RyaXZlcnMvZ3B1L2RybS90 ZWdyYS91YXBpLmMKPj4+PiArKysgYi9kcml2ZXJzL2dwdS9kcm0vdGVncmEvdWFwaS5jCj4+Pj4g QEAgLTMzLDYgKzMzLDkgQEAgc3RhdGljIHZvaWQgdGVncmFfZHJtX2NoYW5uZWxfY29udGV4dF9j bG9zZShzdHJ1Y3QKPj4+PiB0ZWdyYV9kcm1fY29udGV4dCAqY29udGV4dCkKPj4+PiAgwqDCoMKg wqDCoCBzdHJ1Y3QgdGVncmFfZHJtX21hcHBpbmcgKm1hcHBpbmc7Cj4+Pj4gIMKgwqDCoMKgwqAg dW5zaWduZWQgbG9uZyBpZDsKPj4+PiAgwqAgK8KgwqDCoCBpZiAoY29udGV4dC0+bWVtb3J5X2Nv bnRleHQpCj4+Pj4gK8KgwqDCoMKgwqDCoMKgIGhvc3QxeF9jb250ZXh0X3B1dChjb250ZXh0LT5t ZW1vcnlfY29udGV4dCk7Cj4+Pgo+Pj4gVGhlICJpZiAoY29udGV4dC0+bWVtb3J5X2NvbnRleHQg JiYKPj4+IGNvbnRleHQtPmNsaWVudC0+b3BzLT5nZXRfc3RyZWFtaWRfb2Zmc2V0KSIgYWJvdmUg ZG9lc24ndCBtYXRjaCB0aGUgImlmCj4+PiAoY29udGV4dC0+bWVtb3J5X2NvbnRleHQpIi4gWW91 J2xsIGdldCByZWZjb3VudCB1bmRlcmZsb3cuCj4+Cj4+IEFuZCB0aGlzIGRyb3AgaXMgZm9yIHRo ZSByZWZjb3VudCBpbXBsaWNpdGx5IGFkZGVkIHdoZW4gYWxsb2NhdGluZyB0aGUKPj4gbWVtb3J5 IGNvbnRleHQgdGhyb3VnaCBob3N0MXhfY29udGV4dF9hbGxvYzsgc28gdGhlc2UgdHdvIHBsYWNl cyBzaG91bGQKPj4gYmUgaW5kZXBlbmRlbnQuCj4+Cj4+IFBsZWFzZSBlbGFib3JhdGUgaWYgSSBt aXNzZWQgc29tZXRoaW5nLgo+IAo+IFlvdSBuYW1lZCBjb250ZXh0IGFzIG1lbW9yeV9jb250ZXh0 IGFuZCB0aGVuIGhhdmUKPiBjb250ZXh0PWNvbnRleHQtPm1lbW9yeV9jb250ZXh0LiBQbGVhc2Ug dHJ5IHRvIGltcHJvdmUgdGhlIHZhcmlhYmxlCj4gbmFtZXMsIGxpa2UgZHJtX2N0eC0+aG9zdDF4 X2N0eCBmb3IgZXhhbXBsZS4KPiAKPiBJJ20gYWxzbyBub3QgYSBiaWcgZmFuIG9mIHRoZSAiaWYg KHJlZikgcHV0KHJlZikiIHBhdHRlcm4uIFdvbid0IGJlCj4gYmV0dGVyIHRvIG1vdmUgYWxsIHRo ZSAiaWYgKCFOVUxMKSIgY2hlY2tzIGluc2lkZSBvZiBnZXQoKS9wdXQoKSBhbmQKPiBtYWtlIHRo ZSBpbnZvY2F0aW9ucyB1bmNvbmRpdGlvbmFsPwoKSSBhZ3JlZSB0aGF0IHRoZSBuYW1pbmcgaGVy ZSBpcyBjb25mdXNpbmcgd2l0aCBkaWZmZXJlbnQga2luZHMgb2YgCmNvbnRleHRzIGZseWluZyBh cm91bmQsIHRob3VnaCBJIHdvdWxkIHByZWZlciBub3QgdG8gY2hhbmdlIHRoZSBvcmlnaW5hbCAK J3N0cnVjdCB0ZWdyYV9kcm1fY29udGV4dCAqY29udGV4dCcgc2luY2UgaXQncyB1c2VkIGFsbCBh cm91bmQgdGhlIGNvZGUuIApCdXQgSSdsbCB0cnkgdG8gbWFrZSBpdCBjbGVhcmVyLgoKUmVnYXJk aW5nIG1vdmluZyBOVUxMIGNoZWNrcyBpbnNpZGUgZ2V0L3B1dCwgSSBwZXJzb25hbGx5IGRpc2xp a2UgdGhhdCAKcGF0dGVybiAoYWxzbyB3aXRoIGUuZy4ga2ZyZWUpIHNpbmNlIHdoZW4gcmVhZGlu ZyB0aGUgY29kZSwgaXQgbWFrZXMgaXQgCm1vcmUgZGlmZmljdWx0IHRvIHNlZSB0aGF0IHRoZSBw b2ludGVyIGNhbiBiZSBOVUxMLgoKTWlra28KX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX18KaW9tbXUgbWFpbGluZyBsaXN0CmlvbW11QGxpc3RzLmxpbnV4LWZv dW5kYXRpb24ub3JnCmh0dHBzOi8vbGlzdHMubGludXhmb3VuZGF0aW9uLm9yZy9tYWlsbWFuL2xp c3RpbmZvL2lvbW11 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 2C740C4332F for ; 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Received: from 91-158-25-70.elisa-laajakaista.fi ([91.158.25.70] helo=[192.168.1.10]) by mail.kapsi.fi with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1nMQfS-00063Y-Iy; Tue, 22 Feb 2022 10:37:06 +0200 Message-ID: <134c4a28-4331-deed-a374-75c9711168f0@kapsi.fi> Date: Tue, 22 Feb 2022 10:37:05 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [PATCH v3 9/9] drm/tegra: Support context isolation Content-Language: en-US To: Dmitry Osipenko , Mikko Perttunen , thierry.reding@gmail.com, jonathanh@nvidia.com, joro@8bytes.org, will@kernel.org, robh+dt@kernel.org, robin.murphy@arm.com References: <20220218113952.3077606-1-mperttunen@nvidia.com> <20220218113952.3077606-10-mperttunen@nvidia.com> <2b4dd244-f918-4d26-2322-00a0bb226ccf@gmail.com> From: Mikko Perttunen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 91.158.25.70 X-SA-Exim-Mail-From: cyndis@kapsi.fi X-SA-Exim-Scanned: No (on mail.kapsi.fi); SAEximRunCond expanded to false X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linux-tegra@vger.kernel.org, linux-arm-kernel@lists.infradead.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 2/21/22 22:02, Dmitry Osipenko wrote: > 21.02.2022 15:06, Mikko Perttunen пишет: >> On 2/19/22 20:35, Dmitry Osipenko wrote: >>> 18.02.2022 14:39, Mikko Perttunen пишет: >>>> +    if (context->memory_context && >>>> context->client->ops->get_streamid_offset) { >>>              ^^^ >>>> +        int offset = >>>> context->client->ops->get_streamid_offset(context->client); >>>> + >>>> +        if (offset >= 0) { >>>> +            job->context = context->memory_context; >>>> +            job->engine_streamid_offset = offset; >>>> +            host1x_context_get(job->context); >>>> +        } >>> >>> You should bump refcount unconditionally or you'll get refcnt underflow >>> on put, when offset < 0. >> >> This refcount is intended to be dropped from 'release_job', where it's >> dropped if job->context is set, which it is from this path. >> >>> >>>> +    } >>>> + >>>>       /* >>>>        * job_data is now part of job reference counting, so don't >>>> release >>>>        * it from here. >>>> diff --git a/drivers/gpu/drm/tegra/uapi.c b/drivers/gpu/drm/tegra/uapi.c >>>> index 9ab9179d2026..be33da54d12c 100644 >>>> --- a/drivers/gpu/drm/tegra/uapi.c >>>> +++ b/drivers/gpu/drm/tegra/uapi.c >>>> @@ -33,6 +33,9 @@ static void tegra_drm_channel_context_close(struct >>>> tegra_drm_context *context) >>>>       struct tegra_drm_mapping *mapping; >>>>       unsigned long id; >>>>   +    if (context->memory_context) >>>> +        host1x_context_put(context->memory_context); >>> >>> The "if (context->memory_context && >>> context->client->ops->get_streamid_offset)" above doesn't match the "if >>> (context->memory_context)". You'll get refcount underflow. >> >> And this drop is for the refcount implicitly added when allocating the >> memory context through host1x_context_alloc; so these two places should >> be independent. >> >> Please elaborate if I missed something. > > You named context as memory_context and then have > context=context->memory_context. Please try to improve the variable > names, like drm_ctx->host1x_ctx for example. > > I'm also not a big fan of the "if (ref) put(ref)" pattern. Won't be > better to move all the "if (!NULL)" checks inside of get()/put() and > make the invocations unconditional? I agree that the naming here is confusing with different kinds of contexts flying around, though I would prefer not to change the original 'struct tegra_drm_context *context' since it's used all around the code. But I'll try to make it clearer. Regarding moving NULL checks inside get/put, I personally dislike that pattern (also with e.g. kfree) since when reading the code, it makes it more difficult to see that the pointer can be NULL. Mikko 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 9F27FC433EF for ; Tue, 22 Feb 2022 08:38:26 +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:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc: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=aLlvSI6AzaOUPORyma7EjT+OkbFZFeUoY6/OpmxFAz8=; b=cvJgc21OTWnTxZ ATFrptGKwYFEjCdsKy0H6snsi2tfzNYtrbH471k4+O9u/y1C0sd1FGyvh+kbk1iIbr9MKOeMR6rMO S1E4Af+HS2AXux+Ttio59/RlBr6/Zz6XuNX9Fpq7ljtMwPh7p9goGh939lVUv0DTmJtX3y+w/Y2sE 6pffwdN3AqsUhQ2OGEe7UXIhlXETYP4ceqorzgfhighWjnqnex2W51/5coevcfUbqcmJMpfcf2IFQ d7Dd3J24eXxQAZKKbHWXUSBzXU+8xgH2wofoXEjaf/xhmqa5ZqZwmnn8AQOaUZSyHN2MQdUlcLSv1 b3xpecXI1dLMo/QbFaCg==; 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Received: from 91-158-25-70.elisa-laajakaista.fi ([91.158.25.70] helo=[192.168.1.10]) by mail.kapsi.fi with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1nMQfS-00063Y-Iy; Tue, 22 Feb 2022 10:37:06 +0200 Message-ID: <134c4a28-4331-deed-a374-75c9711168f0@kapsi.fi> Date: Tue, 22 Feb 2022 10:37:05 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [PATCH v3 9/9] drm/tegra: Support context isolation Content-Language: en-US To: Dmitry Osipenko , Mikko Perttunen , thierry.reding@gmail.com, jonathanh@nvidia.com, joro@8bytes.org, will@kernel.org, robh+dt@kernel.org, robin.murphy@arm.com Cc: linux-tegra@vger.kernel.org, dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20220218113952.3077606-1-mperttunen@nvidia.com> <20220218113952.3077606-10-mperttunen@nvidia.com> <2b4dd244-f918-4d26-2322-00a0bb226ccf@gmail.com> From: Mikko Perttunen In-Reply-To: X-SA-Exim-Connect-IP: 91.158.25.70 X-SA-Exim-Mail-From: cyndis@kapsi.fi X-SA-Exim-Scanned: No (on mail.kapsi.fi); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220222_003717_536663_983C3A5D X-CRM114-Status: GOOD ( 17.93 ) 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: , 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 T24gMi8yMS8yMiAyMjowMiwgRG1pdHJ5IE9zaXBlbmtvIHdyb3RlOgo+IDIxLjAyLjIwMjIgMTU6 MDYsIE1pa2tvIFBlcnR0dW5lbiDQv9C40YjQtdGCOgo+PiBPbiAyLzE5LzIyIDIwOjM1LCBEbWl0 cnkgT3NpcGVua28gd3JvdGU6Cj4+PiAxOC4wMi4yMDIyIDE0OjM5LCBNaWtrbyBQZXJ0dHVuZW4g 0L/QuNGI0LXRgjoKPj4+PiArwqDCoMKgIGlmIChjb250ZXh0LT5tZW1vcnlfY29udGV4dCAmJgo+ Pj4+IGNvbnRleHQtPmNsaWVudC0+b3BzLT5nZXRfc3RyZWFtaWRfb2Zmc2V0KSB7Cj4+PiAgwqDC oMKgwqDCoMKgwqDCoMKgwqDCoMKgIF5eXgo+Pj4+ICvCoMKgwqDCoMKgwqDCoCBpbnQgb2Zmc2V0 ID0KPj4+PiBjb250ZXh0LT5jbGllbnQtPm9wcy0+Z2V0X3N0cmVhbWlkX29mZnNldChjb250ZXh0 LT5jbGllbnQpOwo+Pj4+ICsKPj4+PiArwqDCoMKgwqDCoMKgwqAgaWYgKG9mZnNldCA+PSAwKSB7 Cj4+Pj4gK8KgwqDCoMKgwqDCoMKgwqDCoMKgwqAgam9iLT5jb250ZXh0ID0gY29udGV4dC0+bWVt b3J5X2NvbnRleHQ7Cj4+Pj4gK8KgwqDCoMKgwqDCoMKgwqDCoMKgwqAgam9iLT5lbmdpbmVfc3Ry ZWFtaWRfb2Zmc2V0ID0gb2Zmc2V0Owo+Pj4+ICvCoMKgwqDCoMKgwqDCoMKgwqDCoMKgIGhvc3Qx eF9jb250ZXh0X2dldChqb2ItPmNvbnRleHQpOwo+Pj4+ICvCoMKgwqDCoMKgwqDCoCB9Cj4+Pgo+ Pj4gWW91IHNob3VsZCBidW1wIHJlZmNvdW50IHVuY29uZGl0aW9uYWxseSBvciB5b3UnbGwgZ2V0 IHJlZmNudCB1bmRlcmZsb3cKPj4+IG9uIHB1dCwgd2hlbiBvZmZzZXQgPCAwLgo+Pgo+PiBUaGlz IHJlZmNvdW50IGlzIGludGVuZGVkIHRvIGJlIGRyb3BwZWQgZnJvbSAncmVsZWFzZV9qb2InLCB3 aGVyZSBpdCdzCj4+IGRyb3BwZWQgaWYgam9iLT5jb250ZXh0IGlzIHNldCwgd2hpY2ggaXQgaXMg ZnJvbSB0aGlzIHBhdGguCj4+Cj4+Pgo+Pj4+ICvCoMKgwqAgfQo+Pj4+ICsKPj4+PiAgwqDCoMKg wqDCoCAvKgo+Pj4+ICDCoMKgwqDCoMKgwqAgKiBqb2JfZGF0YSBpcyBub3cgcGFydCBvZiBqb2Ig cmVmZXJlbmNlIGNvdW50aW5nLCBzbyBkb24ndAo+Pj4+IHJlbGVhc2UKPj4+PiAgwqDCoMKgwqDC oMKgICogaXQgZnJvbSBoZXJlLgo+Pj4+IGRpZmYgLS1naXQgYS9kcml2ZXJzL2dwdS9kcm0vdGVn cmEvdWFwaS5jIGIvZHJpdmVycy9ncHUvZHJtL3RlZ3JhL3VhcGkuYwo+Pj4+IGluZGV4IDlhYjkx NzlkMjAyNi4uYmUzM2RhNTRkMTJjIDEwMDY0NAo+Pj4+IC0tLSBhL2RyaXZlcnMvZ3B1L2RybS90 ZWdyYS91YXBpLmMKPj4+PiArKysgYi9kcml2ZXJzL2dwdS9kcm0vdGVncmEvdWFwaS5jCj4+Pj4g QEAgLTMzLDYgKzMzLDkgQEAgc3RhdGljIHZvaWQgdGVncmFfZHJtX2NoYW5uZWxfY29udGV4dF9j bG9zZShzdHJ1Y3QKPj4+PiB0ZWdyYV9kcm1fY29udGV4dCAqY29udGV4dCkKPj4+PiAgwqDCoMKg wqDCoCBzdHJ1Y3QgdGVncmFfZHJtX21hcHBpbmcgKm1hcHBpbmc7Cj4+Pj4gIMKgwqDCoMKgwqAg dW5zaWduZWQgbG9uZyBpZDsKPj4+PiAgwqAgK8KgwqDCoCBpZiAoY29udGV4dC0+bWVtb3J5X2Nv bnRleHQpCj4+Pj4gK8KgwqDCoMKgwqDCoMKgIGhvc3QxeF9jb250ZXh0X3B1dChjb250ZXh0LT5t ZW1vcnlfY29udGV4dCk7Cj4+Pgo+Pj4gVGhlICJpZiAoY29udGV4dC0+bWVtb3J5X2NvbnRleHQg JiYKPj4+IGNvbnRleHQtPmNsaWVudC0+b3BzLT5nZXRfc3RyZWFtaWRfb2Zmc2V0KSIgYWJvdmUg ZG9lc24ndCBtYXRjaCB0aGUgImlmCj4+PiAoY29udGV4dC0+bWVtb3J5X2NvbnRleHQpIi4gWW91 J2xsIGdldCByZWZjb3VudCB1bmRlcmZsb3cuCj4+Cj4+IEFuZCB0aGlzIGRyb3AgaXMgZm9yIHRo ZSByZWZjb3VudCBpbXBsaWNpdGx5IGFkZGVkIHdoZW4gYWxsb2NhdGluZyB0aGUKPj4gbWVtb3J5 IGNvbnRleHQgdGhyb3VnaCBob3N0MXhfY29udGV4dF9hbGxvYzsgc28gdGhlc2UgdHdvIHBsYWNl cyBzaG91bGQKPj4gYmUgaW5kZXBlbmRlbnQuCj4+Cj4+IFBsZWFzZSBlbGFib3JhdGUgaWYgSSBt aXNzZWQgc29tZXRoaW5nLgo+IAo+IFlvdSBuYW1lZCBjb250ZXh0IGFzIG1lbW9yeV9jb250ZXh0 IGFuZCB0aGVuIGhhdmUKPiBjb250ZXh0PWNvbnRleHQtPm1lbW9yeV9jb250ZXh0LiBQbGVhc2Ug dHJ5IHRvIGltcHJvdmUgdGhlIHZhcmlhYmxlCj4gbmFtZXMsIGxpa2UgZHJtX2N0eC0+aG9zdDF4 X2N0eCBmb3IgZXhhbXBsZS4KPiAKPiBJJ20gYWxzbyBub3QgYSBiaWcgZmFuIG9mIHRoZSAiaWYg KHJlZikgcHV0KHJlZikiIHBhdHRlcm4uIFdvbid0IGJlCj4gYmV0dGVyIHRvIG1vdmUgYWxsIHRo ZSAiaWYgKCFOVUxMKSIgY2hlY2tzIGluc2lkZSBvZiBnZXQoKS9wdXQoKSBhbmQKPiBtYWtlIHRo ZSBpbnZvY2F0aW9ucyB1bmNvbmRpdGlvbmFsPwoKSSBhZ3JlZSB0aGF0IHRoZSBuYW1pbmcgaGVy ZSBpcyBjb25mdXNpbmcgd2l0aCBkaWZmZXJlbnQga2luZHMgb2YgCmNvbnRleHRzIGZseWluZyBh cm91bmQsIHRob3VnaCBJIHdvdWxkIHByZWZlciBub3QgdG8gY2hhbmdlIHRoZSBvcmlnaW5hbCAK J3N0cnVjdCB0ZWdyYV9kcm1fY29udGV4dCAqY29udGV4dCcgc2luY2UgaXQncyB1c2VkIGFsbCBh cm91bmQgdGhlIGNvZGUuIApCdXQgSSdsbCB0cnkgdG8gbWFrZSBpdCBjbGVhcmVyLgoKUmVnYXJk aW5nIG1vdmluZyBOVUxMIGNoZWNrcyBpbnNpZGUgZ2V0L3B1dCwgSSBwZXJzb25hbGx5IGRpc2xp a2UgdGhhdCAKcGF0dGVybiAoYWxzbyB3aXRoIGUuZy4ga2ZyZWUpIHNpbmNlIHdoZW4gcmVhZGlu ZyB0aGUgY29kZSwgaXQgbWFrZXMgaXQgCm1vcmUgZGlmZmljdWx0IHRvIHNlZSB0aGF0IHRoZSBw b2ludGVyIGNhbiBiZSBOVUxMLgoKTWlra28KCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fCmxpbnV4LWFybS1rZXJuZWwgbWFpbGluZyBsaXN0CmxpbnV4LWFy bS1rZXJuZWxAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5mcmFkZWFkLm9yZy9t YWlsbWFuL2xpc3RpbmZvL2xpbnV4LWFybS1rZXJuZWwK