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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 22A4EC43331 for ; Mon, 11 Nov 2019 16:25:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F14F320679 for ; Mon, 11 Nov 2019 16:25:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727032AbfKKQZS (ORCPT ); Mon, 11 Nov 2019 11:25:18 -0500 Received: from mout.kundenserver.de ([217.72.192.74]:50497 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726910AbfKKQZS (ORCPT ); Mon, 11 Nov 2019 11:25:18 -0500 Received: from mail-qt1-f179.google.com ([209.85.160.179]) by mrelayeu.kundenserver.de (mreue106 [212.227.15.145]) with ESMTPSA (Nemesis) id 1MOiYD-1iGFr137Dr-00QDpb for ; Mon, 11 Nov 2019 17:25:16 +0100 Received: by mail-qt1-f179.google.com with SMTP id g50so16253889qtb.4 for ; Mon, 11 Nov 2019 08:25:16 -0800 (PST) X-Gm-Message-State: APjAAAXu8KhZYr9sGDPSRQgqVrLJ2lBtXvxM6xwtYZ2xvnvKIT6l293y uHa+LK2QXAS/GUJf2WDgeFdcSnl5x3cAI/OJkl0= X-Google-Smtp-Source: APXvYqzhEX+Ry63FPgxImqPVdNg3+01We4bix3tpiOsVLV3c4EpCOOaUFn43GI00Tsjcb2HTxmGTLXXXT8IHHLMKa0E= X-Received: by 2002:ac8:18eb:: with SMTP id o40mr26604573qtk.304.1573489515656; Mon, 11 Nov 2019 08:25:15 -0800 (PST) MIME-Version: 1.0 References: <20191108213257.3097633-1-arnd@arndb.de> <20191108213257.3097633-16-arnd@arndb.de> <3a0cfce79620152facfe31b442a735db1dcda436.camel@pengutronix.de> <7379bfe6c530132caab4cd930cd94f0e28c935ff.camel@pengutronix.de> In-Reply-To: <7379bfe6c530132caab4cd930cd94f0e28c935ff.camel@pengutronix.de> From: Arnd Bergmann Date: Mon, 11 Nov 2019 17:24:59 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 15/16] drm/etnaviv: use ktime_t for timeouts To: Lucas Stach Cc: y2038 Mailman List , David Airlie , Daniel Vetter , =?UTF-8?Q?Guido_G=C3=BCnther?= , "linux-kernel@vger.kernel.org" , dri-devel , The etnaviv authors , Russell King , Sam Ravnborg , =?UTF-8?Q?Christian_K=C3=B6nig?= , Emil Velikov Content-Type: text/plain; charset="UTF-8" X-Provags-ID: V03:K1:JHnu4qBIDr0AeRGo2cjWt8VCwhOw5IiHIztxB1kU5f7R5MHak0b MUhl14MFo3fS2u3qB6cwVV33jE07KSe979aZ8K5PmFEMMOJL4b2T0l2gnPOKx6lcxsD2fDq 9XnWN2B4fBlWpV0HfeteryhY78xhDjNQ0mQNLV6GYtVlUz7reGx9QmA4aSAPZZ7iP/Ezb7X ELy6MxULVkSG8blbPxWjw== X-UI-Out-Filterresults: notjunk:1;V03:K0:WJQ11S94CGw=:RutZ7RQyzb5LCYyWCXrCdg RH0Ew62Ok670uFYGEARvFFMPRKx+hyo/MYHh51VvgWm0Wg9SrjzbvS7DtG8lyXnyj+lRXGvRi mtrG7yrlaHuCfQWLpuMI7FDNMeEuWQy/429+zcmda6jn4BgfLctLAw8AxZUvQbZOA2L9VtuUt 6GH16g4JmkuokrDTIaokCEqOQPJY3pIQbApgOkfvRIK3ITqptGJywimY/navkIWbgz9LahCB7 v2GWL8F1KMzhJ532wBvPmboO+2rYYW6jjPaPuTaoVymRiwIG3rd0SIFxvHOze6Dkb7AGS1d0m onjGU0h24kamjW98HG0syPjW5UEkvjHwclqiHvrZfrKcrOj1caM6xdZ+vwXz4aldTLp8Novrx RFEL662SNMVtcz3CzM+FGtqVJNRhHmbFGcoRh+RozIAYq2utWcX/uKBJ4p9r3sfgJD4qdcjxR SKWwaSlJYTlyLej+Am2aUaeKkxHV1ZZFkdWqroLccda3DWbINouYbop2lixk46+VDxc92Qcrf rLptY9j7K0FLMPMELlEYh0Aa5C5stSpQJhO/0P4y3sMCuR3Yw1hFTFd3p/QfRCKgkf3cVXW/4 6RhH5Lnx3h8DdwSCSMr68gHCPodUtyNIJnrY51OZuzqld7vLa2dSqssb+ZEfsr3bVbaZRvDsT l4g3cJYQwoyHITz70qenAafTXb/t9WRAYtTo5lg5bMkyJPcB89hfgUT5PMGnm/7w1WbWVgiIP osEKtc/2rRFCbS0bisXXivKy1n7T5z1tpPWkhcTEJqNu+z1IA+N7bFzfONgN2uJxOyLhUC7Gk kOG0GfcwlVCWDAmVqQ7UpPq89QzWGC0M/vou1C/hr5H7N4XIXlOzhhc+4tEBF+v86+WpsHgm/ /tH2zu/6pORxCMK83yWQ== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 11, 2019 at 10:55 AM Lucas Stach wrote: > > > > > If that's the case then we should never encounter a genuine 0 timeout > > > and this change would be okay. > > > > That's quite likely, I'd say any program passing {0,0} as a timeout without > > ETNA_WAIT_NONBLOCK is already broken, but if we leave it like that, > > it would be best to describe the reasoning in the changelog. > > > > Should I change the changelog, or change the patch to restore the > > current behavior instead? > > > > I guess I could fold the change below into my patch to make it transparent > > to the application again. > > If we assume 0 to never be a valid timeout, due to monotonic clock > starting at 0 and never wrapping then I think we shouldn't introduce > any additional code complexity to fix up the return value for this > specific case. I'm not aware of any etnaviv userspace being broken in > this way to rely on the return value for an invalid timeout input. > > Please just amend the commit message to mention the change in behavior > and why we think it is safe to do. Russell had some additional concerns that he raised on IRC, and I did a new simpler implementation of the patch, plus a related bugfix. Please have a look at those. Arnd 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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 7EEBCC43331 for ; Mon, 11 Nov 2019 16:25:22 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 5FD5820679 for ; Mon, 11 Nov 2019 16:25:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5FD5820679 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arndb.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1FA1C6E946; Mon, 11 Nov 2019 16:25:21 +0000 (UTC) Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.126.133]) by gabe.freedesktop.org (Postfix) with ESMTPS id 293E36E946; Mon, 11 Nov 2019 16:25:18 +0000 (UTC) Received: from mail-qt1-f169.google.com ([209.85.160.169]) by mrelayeu.kundenserver.de (mreue009 [212.227.15.129]) with ESMTPSA (Nemesis) id 1MtwQm-1hcEOu3QUu-00uMby; Mon, 11 Nov 2019 17:25:17 +0100 Received: by mail-qt1-f169.google.com with SMTP id t20so16245210qtn.9; Mon, 11 Nov 2019 08:25:16 -0800 (PST) X-Gm-Message-State: APjAAAVocy9fe3OyxP9lRnqq6JWaHQ2EKZXc2sAovc2C0tsVETqWen7T 4ks2zjDeOrpKVLLlNp49H4rBNioKEnWVAGdCn+M= X-Google-Smtp-Source: APXvYqzhEX+Ry63FPgxImqPVdNg3+01We4bix3tpiOsVLV3c4EpCOOaUFn43GI00Tsjcb2HTxmGTLXXXT8IHHLMKa0E= X-Received: by 2002:ac8:18eb:: with SMTP id o40mr26604573qtk.304.1573489515656; Mon, 11 Nov 2019 08:25:15 -0800 (PST) MIME-Version: 1.0 References: <20191108213257.3097633-1-arnd@arndb.de> <20191108213257.3097633-16-arnd@arndb.de> <3a0cfce79620152facfe31b442a735db1dcda436.camel@pengutronix.de> <7379bfe6c530132caab4cd930cd94f0e28c935ff.camel@pengutronix.de> In-Reply-To: <7379bfe6c530132caab4cd930cd94f0e28c935ff.camel@pengutronix.de> From: Arnd Bergmann Date: Mon, 11 Nov 2019 17:24:59 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 15/16] drm/etnaviv: use ktime_t for timeouts To: Lucas Stach X-Provags-ID: V03:K1:TX9eDjE5QT/+4mxM9rQ1BaNqeRkgbmbFVOyYdXCJZdswN6Zxwtc 7b1CLv9dqOUue6c3qOSQt/apkPVXdeoq+VSl0qtcPmpPRHej+zqjLtFJr6rcq1zcA2qlZrY rPSD6qiqs6QuGLaSXt+umOONbW+VTb27XIGcaG0FcQlc4VmOczJ7O8UWeXHXm9clf36Qu7B 7a1VPKHhToxRQtVwbJzPA== X-UI-Out-Filterresults: notjunk:1;V03:K0:YDqU36Nicqg=:ATQe/O/YoWw5W5kVvkFRRP FyczyCcHhy9P0QTJmNZmQAEVWbVQ7D0qiY6VAhJnNQylR0GCLHjF6VAf7+FbAiar1bKultZfG DVh0OvT5pdeHQBdaLgOQejnF8bfyR5Pegy2uurGoXLMrXTUz3F+VqmQBT2gQP7Ma3ZrRAX2e/ UJQB/YtqUVHLtcY8bOUR9UbxH4Mt3B/f6pH8nScOPL52yEVmlluMlahAzbPKcWEzlu+xqfEpJ SceSTGSa1dx8GfDjXkZ5eVz1yYo87tXTJg4MqLPDgLU1JV1bRRtRME66Q1YKVG+qlUqoJDDg1 n0+f5is3+ZCl0kLH+8d9RbFE4Re+ykBtWaUOAU7EqM7HqEqry8tqUf+FuZriq6o/dSPowwvIT syRVtJMTQdXTv42SJIx7fzKk1eVM3rZhUng2qIVsyrmZ0VyOYMp4Tb7KHHAo/TYxEhsGU2nFH 2y6xDZdEX8ZkKmMkFBODclVqaUfb0BiRa0JKq2BO1JfhlIwHs0G5AVTUbdIqH0JD4aPwukjap K9kpJCdHZnM9uvaVmYgdFGi60nx29RztZMfRPJlFfuyXKLaFnLaj3bdae9ei5VRtdN7eMwxt2 702u+ctTOED5oQWvXvTh7wP5/r9eR48urIpIvWSw4dIHv0+s9H0fRcfHaE3NTrke1BxrsoC93 Ps9sBBOe3ISiFTCVjw82sH10cPdRy6NSo//6633HUj5XUQIXF+nZ3RCUHLhVAiYiipP4slBqz D2v++xLajos3gJW9x62pDx102rGcV+7DRP1F/Vj7JuljvJG9++ThQTLgcNg7Ug7ODVokgBG9v OtN0CZeA33LmejPRKUX9S2kuPuy/z1vqH7RlbuNN3uBC/HOcLxPWGySkYusQYhVjABj+OUlBT cNQkKNv+966Gyd5lH0ag== X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: y2038 Mailman List , =?UTF-8?Q?Guido_G=C3=BCnther?= , "linux-kernel@vger.kernel.org" , dri-devel , The etnaviv authors , David Airlie , Russell King , Sam Ravnborg , =?UTF-8?Q?Christian_K=C3=B6nig?= , Emil Velikov Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Message-ID: <20191111162459.GB_pbuJaMgc8n_pmIOSk7sxhP_-6rbHGxsl_mS3mkdg@z> T24gTW9uLCBOb3YgMTEsIDIwMTkgYXQgMTA6NTUgQU0gTHVjYXMgU3RhY2ggPGwuc3RhY2hAcGVu Z3V0cm9uaXguZGU+IHdyb3RlOgo+ID4KPiA+ID4gSWYgdGhhdCdzIHRoZSBjYXNlIHRoZW4gd2Ug c2hvdWxkIG5ldmVyIGVuY291bnRlciBhIGdlbnVpbmUgMCB0aW1lb3V0Cj4gPiA+IGFuZCB0aGlz IGNoYW5nZSB3b3VsZCBiZSBva2F5Lgo+ID4KPiA+IFRoYXQncyBxdWl0ZSBsaWtlbHksIEknZCBz YXkgYW55IHByb2dyYW0gcGFzc2luZyB7MCwwfSBhcyBhIHRpbWVvdXQgd2l0aG91dAo+ID4gRVRO QV9XQUlUX05PTkJMT0NLIGlzIGFscmVhZHkgYnJva2VuLCBidXQgaWYgd2UgbGVhdmUgaXQgbGlr ZSB0aGF0LAo+ID4gaXQgd291bGQgYmUgYmVzdCB0byBkZXNjcmliZSB0aGUgcmVhc29uaW5nIGlu IHRoZSBjaGFuZ2Vsb2cuCj4gPgo+ID4gU2hvdWxkIEkgY2hhbmdlIHRoZSBjaGFuZ2Vsb2csIG9y IGNoYW5nZSB0aGUgcGF0Y2ggdG8gcmVzdG9yZSB0aGUKPiA+IGN1cnJlbnQgYmVoYXZpb3IgaW5z dGVhZD8KPiA+Cj4gPiBJIGd1ZXNzIEkgY291bGQgZm9sZCB0aGUgY2hhbmdlIGJlbG93IGludG8g bXkgcGF0Y2ggdG8gbWFrZSBpdCB0cmFuc3BhcmVudAo+ID4gdG8gdGhlIGFwcGxpY2F0aW9uIGFn YWluLgo+Cj4gSWYgd2UgYXNzdW1lIDAgdG8gbmV2ZXIgYmUgYSB2YWxpZCB0aW1lb3V0LCBkdWUg dG8gbW9ub3RvbmljIGNsb2NrCj4gc3RhcnRpbmcgYXQgMCBhbmQgbmV2ZXIgd3JhcHBpbmcgdGhl biBJIHRoaW5rIHdlIHNob3VsZG4ndCBpbnRyb2R1Y2UKPiBhbnkgYWRkaXRpb25hbCBjb2RlIGNv bXBsZXhpdHkgdG8gZml4IHVwIHRoZSByZXR1cm4gdmFsdWUgZm9yIHRoaXMKPiBzcGVjaWZpYyBj YXNlLiBJJ20gbm90IGF3YXJlIG9mIGFueSBldG5hdml2IHVzZXJzcGFjZSBiZWluZyBicm9rZW4g aW4KPiB0aGlzIHdheSB0byByZWx5IG9uIHRoZSByZXR1cm4gdmFsdWUgZm9yIGFuIGludmFsaWQg dGltZW91dCBpbnB1dC4KPgo+IFBsZWFzZSBqdXN0IGFtZW5kIHRoZSBjb21taXQgbWVzc2FnZSB0 byBtZW50aW9uIHRoZSBjaGFuZ2UgaW4gYmVoYXZpb3IKPiBhbmQgd2h5IHdlIHRoaW5rIGl0IGlz IHNhZmUgdG8gZG8uCgpSdXNzZWxsIGhhZCBzb21lIGFkZGl0aW9uYWwgY29uY2VybnMgdGhhdCBo ZSByYWlzZWQgb24gSVJDLAphbmQgSSBkaWQgYSBuZXcgc2ltcGxlciBpbXBsZW1lbnRhdGlvbiBv ZiB0aGUgcGF0Y2gsIHBsdXMgYSByZWxhdGVkCmJ1Z2ZpeC4KClBsZWFzZSBoYXZlIGEgbG9vayBh dCB0aG9zZS4KCiAgICAgICBBcm5kCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fCmRyaS1kZXZlbCBtYWlsaW5nIGxpc3QKZHJpLWRldmVsQGxpc3RzLmZyZWVk ZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xpc3RpbmZv L2RyaS1kZXZlbA==