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 E84EAC2D0DB for ; Wed, 22 Jan 2020 11:28:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC03824689 for ; Wed, 22 Jan 2020 11:28:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729159AbgAVL2A (ORCPT ); Wed, 22 Jan 2020 06:28:00 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:2293 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726232AbgAVL2A (ORCPT ); Wed, 22 Jan 2020 06:28:00 -0500 Received: from LHREML710-CAH.china.huawei.com (unknown [172.18.7.108]) by Forcepoint Email with ESMTP id A5A2C9C22FCC24D3ADED; Wed, 22 Jan 2020 11:27:58 +0000 (GMT) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by LHREML710-CAH.china.huawei.com (10.201.108.33) with Microsoft SMTP Server (TLS) id 14.3.408.0; Wed, 22 Jan 2020 11:27:58 +0000 Received: from [127.0.0.1] (10.202.226.43) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Wed, 22 Jan 2020 11:27:51 +0000 Subject: Re: About irq_create_affinity_masks() for a platform device driver To: Thomas Gleixner CC: Marc Zyngier , "linux-kernel@vger.kernel.org" , chenxiang References: <84a9411b-4ae3-1928-3d35-1666f2687ec8@huawei.com> <87o8uveoye.fsf@nanos.tec.linutronix.de> From: John Garry Message-ID: <4b447127-737e-a729-4dc7-82fc8b68af77@huawei.com> Date: Wed, 22 Jan 2020 11:27:50 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <87o8uveoye.fsf@nanos.tec.linutronix.de> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.43] X-ClientProxiedBy: lhreml741-chm.china.huawei.com (10.201.108.191) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 22/01/2020 10:59, Thomas Gleixner wrote: Hi Thomas, > John Garry writes: >> Would there be any issue with a SCSI platform device driver referencing >> this function? >> >> So I have a multi-queue platform device, and I want to spread interrupts >> over all possible CPUs, just like we can do for PCI MSI vectors. This >> topic was touched on in [0]. >> >> And, if so it's ok, could we export that same symbol? > > I think you will need something similar to what we have in the pci/msi > code, but that shouldn't be in your device driver. So I'd rather create > platform infrastructure for this and export that. > That would seem the proper thing do to. So I was doing this for legacy hw as a cheap and quick performance boost, but I doubt how many other users there would be in future for any new API. Also, the effort could be more than the reward and so I may consider dropping the whole idea. But I'll have a play with how the code could look now. Cheers, john