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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 C979FC4361B for ; Wed, 9 Dec 2020 19:14:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 80DA722AAC for ; Wed, 9 Dec 2020 19:14:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387457AbgLITMv (ORCPT ); Wed, 9 Dec 2020 14:12:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:57128 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733106AbgLITMl (ORCPT ); Wed, 9 Dec 2020 14:12:41 -0500 Date: Wed, 9 Dec 2020 20:13:15 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1607541120; bh=/mn3c6w2OPat8G5RrVOMs8d5tNT7UBX9UCtL1Xa3wVM=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=xXVbbdebrU4oDwvk6TgHPsMVqPYEX4Ads4xOd07yxERxy+sHqh8vZScvYuAIfb8Fv dW22xclN90RfewBFKTiT6ABXB7378+Rk6QTFSdf8YwOnocDXg2xxN/g3OnXV0JDCFm EkjGcRIRXchuRsCVmuFtChHaSQOpQmLEXZI2uX1Y= From: Greg KH To: John Garry Cc: jejb@linux.ibm.com, martin.petersen@oracle.com, lenb@kernel.org, rjw@rjwysocki.net, tglx@linutronix.de, maz@kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linuxarm@huawei.com, linux-acpi@vger.kernel.org, dwagner@suse.de Subject: Re: [PATCH v5 4/5] Driver core: platform: Add devm_platform_get_irqs_affinity() Message-ID: References: <1606905417-183214-1-git-send-email-john.garry@huawei.com> <1606905417-183214-5-git-send-email-john.garry@huawei.com> <36730230-9fd7-8c6c-b997-328beea2fc31@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <36730230-9fd7-8c6c-b997-328beea2fc31@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Wed, Dec 09, 2020 at 07:04:02PM +0000, John Garry wrote: > On 09/12/2020 18:32, Greg KH wrote: > > On Wed, Dec 02, 2020 at 06:36:56PM +0800, John Garry wrote: > > > Drivers for multi-queue platform devices may also want managed interrupts > > > for handling HW queue completion interrupts, so add support. > > > > Hi Greg, > > > Why would a platform device want all of this? Shouldn't such a device > > be on a "real" bus instead? > > For this HW version, the device is on the system bus, directly addressable > by the CPU. What do you mean by "system bus"? > Motivation is that I wanted to switch the HW completion queues to use > managed interrupts. Fair enough, seems like overkill for a "platform" bus though :) > > What in-kernel driver needs this complexity? I can't take new apis > > without a real user in the tree, sorry. > > It's in the final patch in the series https://lore.kernel.org/linux-scsi/1606905417-183214-1-git-send-email-john.garry@huawei.com/T/#m0df7e7cd6f0819b99aaeb6b7f8939ef1e17b8a83. Ah, I missed that, I thought that was some high-speed scsi thing, not a tiny platform driver... > I don't anticipate a huge number of users of this API in future, as most > multi-queue devices are PCI devices; so we could do the work of this API in > the driver itself, but the preference was not to export genirq functions > like irq_update_affinity_desc() or irq_create_affinity_masks(), and rather > have a common helper in the core platform code. Ok, I'd like to have the irq maintainers/developers ack this before taking it in the driver core, as someone is going to have to maintain this crazy thing for forever if it gets merged. thanks, greg k-h