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 58053C43217 for ; Wed, 16 Nov 2022 10:09:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232133AbiKPKJo (ORCPT ); Wed, 16 Nov 2022 05:09:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45168 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229703AbiKPKJm (ORCPT ); Wed, 16 Nov 2022 05:09:42 -0500 Received: from bmailout1.hostsharing.net (bmailout1.hostsharing.net [IPv6:2a01:37:1000::53df:5f64:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E8D0F1DDC0; Wed, 16 Nov 2022 02:09:40 -0800 (PST) Received: from h08.hostsharing.net (h08.hostsharing.net [IPv6:2a01:37:1000::53df:5f1c:0]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS DV RSA Mixed SHA256 2020 CA-1" (verified OK)) by bmailout1.hostsharing.net (Postfix) with ESMTPS id 390A13000BA01; Wed, 16 Nov 2022 11:09:39 +0100 (CET) Received: by h08.hostsharing.net (Postfix, from userid 100393) id 269184378B; Wed, 16 Nov 2022 11:09:39 +0100 (CET) Date: Wed, 16 Nov 2022 11:09:39 +0100 From: Lukas Wunner To: ira.weiny@intel.com Cc: Dan Williams , Bjorn Helgaas , Bjorn Helgaas , Gregory Price , Jonathan Cameron , Alison Schofield , Vishal Verma , Ben Widawsky , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH] PCI/doe: Fix work struct declaration Message-ID: <20221116100939.GA32050@wunner.de> References: <20221115011943.1051039-1-ira.weiny@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221115011943.1051039-1-ira.weiny@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 14, 2022 at 05:19:43PM -0800, ira.weiny@intel.com wrote: > From: Ira Weiny > > The callers of pci_doe_submit_task() allocate the pci_doe_task on the > stack. This causes the work structure to be allocated on the stack > without pci_doe_submit_task() knowing. Work item initialization needs > to be done with either INIT_WORK_ONSTACK() or INIT_WORK() depending on > how the work item is allocated. > > Jonathan suggested creating doe task allocation macros such as > DECLARE_CDAT_DOE_TASK_ONSTACK().[1] The issue with this is the work > function is not known to the callers and must be initialized correctly. > > A follow up suggestion was to have an internal 'pci_doe_work' item > allocated by pci_doe_submit_task().[2] This requires an allocation which > could restrict the context where tasks are used. > > Compromise with an intermediate step to initialize the task struct with > a new call pci_doe_init_task() which must be called prior to submit > task. > > [1] https://lore.kernel.org/linux-cxl/20221014151045.24781-1-Jonathan.Cameron@huawei.com/T/#m88a7f50dcce52f30c8bf5c3dcc06fa9843b54a2d > [2] https://lore.kernel.org/linux-cxl/20221014151045.24781-1-Jonathan.Cameron@huawei.com/T/#m63c636c5135f304480370924f4d03c00357be667 We have object_is_on_stack(), included from . So you could just autosense in pci_doe_submit_task() whether pci_doe_task is on the stack and call the appropriate INIT_WORK variant. Any reason not to do that? Thanks, Lukas