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 4C88BC433FE for ; Tue, 8 Nov 2022 05:52:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232243AbiKHFwv (ORCPT ); Tue, 8 Nov 2022 00:52:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230154AbiKHFwu (ORCPT ); Tue, 8 Nov 2022 00:52:50 -0500 Received: from NAM10-MW2-obe.outbound.protection.outlook.com (mail-mw2nam10on2070.outbound.protection.outlook.com [40.107.94.70]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 576772CDFD; Mon, 7 Nov 2022 21:52:49 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=B/GoR7eSwD1qNxNc4ToHTC3yx2VRwrLKzhHvCQXZ6xuVsYFmWgiHIQCY9d8fjs42Sa56U2FVKvqLb4Hg3RFDM7u8OTcYWLkCzohWxOnq8SjiYOznCvFgDxLCfzAWndZ9ugP2VnB3pkKa6A3ETd2IMiw0Y3yn4yyH1m4yurJD+ciSqDTxRw/K2pkWZ6eDaXE86+oAtwW988hf5mbgtSY3nbAf0u2gfkYXnSfYh6DllNalshiEyjLmlMsquGX3joISXyoQKN1/yKW45Mu2JqVEFZrXg4LlYBjMGKD0OknwRgdO1p08b5psqQEBJ7dZdHpAgoN1sa8kckJQL71dYicecg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=x1qW+X7DuxRgSnOjsL0hHHOWZloe6zja3piRnakm1Q0=; b=FS8awZGyuKzm+Xld7+qlhdEZRpwkpcplceDvNGDoquJowhTcFGMQeB68MfTm4I7DaCjZFQHmeSdsZ1i1r/8fmR63D/QDWBW1pzdts4ov1ElNSvMa1c6Bw81AInYDFhVKK0tKXkzVoTCb3/dCAOqCRNul+72TNIqJplI9Hj7NHmvPwSpY9BGXCSfxe7l1ygA/nZHAUg3fyMghXwfwaS9kQPjfmQhmw2gxnTg90NAF5TdGAYSzeBR28CMxH2AaHsrZZEMdQQmI1YM1xSNYAu+BV8C66WIjLCGsQA4udliRBOlCl7Zg+h23dVmET8HcmCh0kFla0SuaPRrLt5C6VU/j2A== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=x1qW+X7DuxRgSnOjsL0hHHOWZloe6zja3piRnakm1Q0=; b=ldHRheWBmTUjs+nwOlpQdsBLx1SvqCCcXzYvfl+igYvuGDjp+zv5QhEG4O4zqhrha5k5vBov+b1tBAQKQrpJ8jFqRZptMDJfRR8F39adsW6ZJY2vRf3qFOHl8W0U0XtZ4+2SJh12EK+3IduSaVYPv1NFqFSgtVSZW7W4rzehsAE= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from BL1PR12MB5827.namprd12.prod.outlook.com (2603:10b6:208:396::19) by IA1PR12MB6236.namprd12.prod.outlook.com (2603:10b6:208:3e4::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5791.27; Tue, 8 Nov 2022 05:52:47 +0000 Received: from BL1PR12MB5827.namprd12.prod.outlook.com ([fe80::87b1:d413:9ef0:9af]) by BL1PR12MB5827.namprd12.prod.outlook.com ([fe80::87b1:d413:9ef0:9af%6]) with mapi id 15.20.5791.025; Tue, 8 Nov 2022 05:52:47 +0000 Message-ID: <1f673c67-f1ea-318b-b110-a4520d76ff59@amd.com> Date: Tue, 8 Nov 2022 11:22:36 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH v4 4/5] PCI: endpoint: Use callback mechanism for passing events from EPC to EPF Content-Language: en-US To: Manivannan Sadhasivam , kishon@kernel.org, lpieralisi@kernel.org, bhelgaas@google.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, kw@linux.com, robh@kernel.org, vidyas@nvidia.com, vigneshr@ti.com References: <20221025145101.116393-1-manivannan.sadhasivam@linaro.org> <20221025145101.116393-5-manivannan.sadhasivam@linaro.org> From: Kishon Vijay Abraham I In-Reply-To: <20221025145101.116393-5-manivannan.sadhasivam@linaro.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: PN3PR01CA0130.INDPRD01.PROD.OUTLOOK.COM (2603:1096:c01:bf::19) To BL1PR12MB5827.namprd12.prod.outlook.com (2603:10b6:208:396::19) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL1PR12MB5827:EE_|IA1PR12MB6236:EE_ X-MS-Office365-Filtering-Correlation-Id: 5b4c4d61-d0cc-416f-830f-08dac14d7677 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BL1PR12MB5827.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(4636009)(376002)(136003)(366004)(396003)(346002)(39860400002)(451199015)(26005)(66946007)(38100700002)(8676002)(66556008)(66476007)(4326008)(2616005)(186003)(316002)(53546011)(31686004)(2906002)(36756003)(5660300002)(6506007)(41300700001)(6666004)(8936002)(7416002)(6512007)(31696002)(83380400001)(6486002)(478600001)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?cmVwV1FoNlJNVkVUSVJvVm9QNmxOeDFFZk9HSTBkZktPeHlpbXhkeWRSMXRL?= =?utf-8?B?amVrRlFKaVJVdzdBdGgramtOeWNqaDV6R2ZQV21hcTJVeE95UnpsaHVOMTU0?= =?utf-8?B?Y3d2MmtCUUJjZFphbFlxQ1JDTVl5Mk1UenJkTzk4eE92OVpnU0cvWDlPdkhh?= =?utf-8?B?RVlVcUJkUHBtTnRyTkhrYzh1bjZ2L2pDZFR2NVQ4RVRiVUROSHZBWDRLLy8w?= =?utf-8?B?eXpSSGVheWlrL3BZMytoVk5NUmtNSFZhYU5tODFKc1RmelZRK2RETUZWN2hU?= =?utf-8?B?dDJmTkZEOHJmaUZDcVRSYU04cGhUTllRUVE2UEhjMzYvNjNtMzVybm1OWlE2?= =?utf-8?B?YU0xMForYmkyVjZpYXlSYzFQQXREOFA1eUw4QVRBK3MzU1VBSjFTYThyNXhi?= =?utf-8?B?UFlTSG8yZUlwemw0azJJVzVDNFhRM3ZvTGVwSERVa014WkV6MGxpT0VaQkRH?= =?utf-8?B?UkdiSjM4Q2JFSkhIZmx6RDVWcnFmRFJRVDFPSm4rU3owMVBpNWZmSi9FWEJo?= =?utf-8?B?SlJlQXRLZXZBVXhoWDYrSzdHVXRwbHBVWUZtaHF1WDBVZVRUMC82TW5KQmZ5?= =?utf-8?B?ZDAycHdtZ1BmZUpUdGhpNXFZRnpCOERxMVJNdzRmT1RoM0lBR0tJdGJMRlE3?= =?utf-8?B?K0Rrakg2QW1GQTV4YktjV2dqa0FFd0tER2NPL3Y1N2pyeHpjMWZRamlNRllX?= =?utf-8?B?ZDVzUnZ3dWpxNFdsRktXb3pHbUprM1lTRHpBaWVlQ2Nhb1FaMWo5MFU0V1BP?= =?utf-8?B?WUNUTmVOZzR5eUtFd0NBY0xRMDhYaCsvV0tqc0wrbVpWV2tkb3pXZXNONW4v?= =?utf-8?B?dEU1Y1g3WUZHTCtOb01BSlNPUTJtQkcwY0M3bllzYUkvWk5KV25mNHR2NERV?= =?utf-8?B?bEk2Nkp3N0d0cDJOdWZRTWFVZjJVMktvU0hwVkQyeXdSb1FJN2NVMjlQRjF1?= =?utf-8?B?NHdGcFMxeC9vN2V5OHowc2VFZVZLcTZJTkRqa0hpT3BzRW56eEN1akNpZmY2?= =?utf-8?B?UGRQbVZiY21tbWY2QUJwM04xSG9NdUpwN0RveXk1bHR5N1pqVUlCczd6dnZK?= =?utf-8?B?b05seS9RRGVaQjNjd0daL3V0NVBvbmI2b05qV2NWeUxHWnBqRy9hSmpyTEVx?= =?utf-8?B?SmttRng2S21UcStmeXM1SktGWFNIdlJqTDRiaVBiLzJhV0dMaUpoY1crVEdp?= =?utf-8?B?RVlCRml0WlB6NVBMZnQ5TEpjdUFpVUJOQXl4R0VSa2hzbGF4SWJBT1M3ZWRs?= =?utf-8?B?eHpMN3pmWWxwL1lSUS9Femd0MERaYzlEekM0bFdNSlNKZENyRzRRdTdaVmFT?= =?utf-8?B?ZkhrakZFeGFiTFZzTFVHdTEzODMwWS9FMXQwQWZFb2FRa212Z0JuZzlkcCtr?= =?utf-8?B?TUVjTW1LQUZNT1QxK1k1Sk1TbVFTcUwrSHBoUWxnaUpkS3h0aVlaMndUS1Fq?= =?utf-8?B?OVErNEJ1Q1NSejZxdUt1UWxzcllJNUpCeUhKNjZkSFd3N2NCZTJqTTRSbFRp?= =?utf-8?B?SlEvYXFWTHkvMWZORmJEM25WRHFlV25ZTUM0cHhjSVNRazhZc3hxQlM5UmRY?= =?utf-8?B?bVBha3FPRTlZbHIrTWxXdmhYbzZNU3MwN0RoNWxhZjlIOHloWk1EMEFOWDdx?= =?utf-8?B?NFVNOFhYYjFHUjByeFNOSmlvd3Z3Q1FXU3pDSTl1V2FqMTBwclZWbXlYNlh5?= =?utf-8?B?R1NkMEZ1T0dCV01XZmYyQmtUQzV1VW9WUTFRMXJMSnZTclF4QUZ1bFBoN0g0?= =?utf-8?B?RXJhNmNMZjYyQkhLa0pTeUZqVzlvMmN0c1p3YXNnMk9hS0VkQmxYdmFmWkVm?= =?utf-8?B?bDRZd0NsVTJRQ2lOc2hJbk9HdUgxbEwvbys0ZS93bEZuS1YxNDJEWVZPVjVO?= =?utf-8?B?Y0g1R09vTHJ5bjRFQzhlcG5tU3hZSVNTVVNldFhDR3ZJbU93VVVJbm14UTd4?= =?utf-8?B?d0ZGMVErR2M4YzZGeTN2aVJCc3RleUZzdjVDcTk3cEhCa2p1NGNCNlNwQmRB?= =?utf-8?B?TWsyVklaYW9LV215QTEwWUZvMGlueTh1OFI1S3UxbXBrcDZ1dVpQbDVZRVV5?= =?utf-8?B?YTQ2OUoxN2xzUW0vdnVqM0JxSWNySXpRUzUzY092bk9FWFNrdXUydXA3QXM3?= =?utf-8?Q?DBdleyJevb8KK6Ol4+vcbkIP3?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5b4c4d61-d0cc-416f-830f-08dac14d7677 X-MS-Exchange-CrossTenant-AuthSource: BL1PR12MB5827.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Nov 2022 05:52:47.3657 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: +pqlvmUJZhiTxqEcE8pyUAOe2rBTB91/Rt0EU3jSrmmAXz0Z+CH9PSla0W5J473S7riEMVWiBAXebQrrtFr0Ng== X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB6236 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 10/25/2022 8:21 PM, Manivannan Sadhasivam wrote: > Instead of using the notifiers for passing the events from EPC to EPF, > let's introduce a callback based mechanism where the EPF drivers can > populate relevant callbacks for EPC events they want to subscribe. > > The use of notifiers in kernel is not recommended if there is a real link > between the sender and receiver, like in this case. Also, the existing > atomic notifier forces the notification functions to be in atomic context > while the caller may be in non-atomic context. For instance, the two > in-kernel users of the notifiers, pcie-qcom and pcie-tegra194, both are > calling the notifier functions in non-atomic context (from threaded IRQ > handlers). This creates a sleeping in atomic context issue with the > existing EPF_TEST driver that calls the EPC APIs that may sleep. > > For all these reasons, let's get rid of the notifier chains and use the > simple callback mechanism for signalling the events from EPC to EPF > drivers. This preserves the context of the caller and avoids the latency > of going through a separate interface for triggering the notifications. > > As a first step of the transition, the core_init() callback is introduced > in this commit, that'll replace the existing CORE_INIT notifier used for > signalling the init complete event from EPC. > > During the occurrence of the event, EPC will go over the list of EPF > drivers attached to it and will call the core_init() callback if available. > > Signed-off-by: Manivannan Sadhasivam Acked-by: Kishon Vijay Abraham I > --- > drivers/pci/endpoint/functions/pci-epf-test.c | 13 ++++++------- > drivers/pci/endpoint/pci-epc-core.c | 11 ++++++++++- > include/linux/pci-epf.h | 11 ++++++++++- > 3 files changed, 26 insertions(+), 9 deletions(-) > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c > index a6f906a96669..868de17e1ad2 100644 > --- a/drivers/pci/endpoint/functions/pci-epf-test.c > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c > @@ -826,20 +826,17 @@ static int pci_epf_test_core_init(struct pci_epf *epf) > return 0; > } > > +static const struct pci_epc_event_ops pci_epf_test_event_ops = { > + .core_init = pci_epf_test_core_init, > +}; > + > static int pci_epf_test_notifier(struct notifier_block *nb, unsigned long val, > void *data) > { > struct pci_epf *epf = container_of(nb, struct pci_epf, nb); > struct pci_epf_test *epf_test = epf_get_drvdata(epf); > - int ret; > > switch (val) { > - case CORE_INIT: > - ret = pci_epf_test_core_init(epf); > - if (ret) > - return NOTIFY_BAD; > - break; > - > case LINK_UP: > queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler, > msecs_to_jiffies(1)); > @@ -1010,6 +1007,8 @@ static int pci_epf_test_probe(struct pci_epf *epf, const struct pci_epf_device_i > > INIT_DELAYED_WORK(&epf_test->cmd_handler, pci_epf_test_cmd_handler); > > + epf->event_ops = &pci_epf_test_event_ops; > + > epf_set_drvdata(epf, epf_test); > return 0; > } > diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c > index 6cce430d431b..8bb60528f530 100644 > --- a/drivers/pci/endpoint/pci-epc-core.c > +++ b/drivers/pci/endpoint/pci-epc-core.c > @@ -707,10 +707,19 @@ EXPORT_SYMBOL_GPL(pci_epc_linkup); > */ > void pci_epc_init_notify(struct pci_epc *epc) > { > + struct pci_epf *epf; > + > if (!epc || IS_ERR(epc)) > return; > > - atomic_notifier_call_chain(&epc->notifier, CORE_INIT, NULL); > + mutex_lock(&epc->list_lock); > + list_for_each_entry(epf, &epc->pci_epf, list) { > + mutex_lock(&epf->lock); > + if (epf->event_ops && epf->event_ops->core_init) > + epf->event_ops->core_init(epf); > + mutex_unlock(&epf->lock); > + } > + mutex_unlock(&epc->list_lock); > } > EXPORT_SYMBOL_GPL(pci_epc_init_notify); > > diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h > index 0c94cc1513bc..a06f3b4c8bee 100644 > --- a/include/linux/pci-epf.h > +++ b/include/linux/pci-epf.h > @@ -18,7 +18,6 @@ struct pci_epf; > enum pci_epc_interface_type; > > enum pci_notify_event { > - CORE_INIT, > LINK_UP, > }; > > @@ -72,6 +71,14 @@ struct pci_epf_ops { > struct config_group *group); > }; > > +/** > + * struct pci_epf_event_ops - Callbacks for capturing the EPC events > + * @core_init: Callback for the EPC initialization complete event > + */ > +struct pci_epc_event_ops { > + int (*core_init)(struct pci_epf *epf); > +}; > + > /** > * struct pci_epf_driver - represents the PCI EPF driver > * @probe: ops to perform when a new EPF device has been bound to the EPF driver > @@ -140,6 +147,7 @@ struct pci_epf_bar { > * @is_vf: true - virtual function, false - physical function > * @vfunction_num_map: bitmap to manage virtual function number > * @pci_vepf: list of virtual endpoint functions associated with this function > + * @event_ops: Callbacks for capturing the EPC events > */ > struct pci_epf { > struct device dev; > @@ -170,6 +178,7 @@ struct pci_epf { > unsigned int is_vf; > unsigned long vfunction_num_map; > struct list_head pci_vepf; > + const struct pci_epc_event_ops *event_ops; > }; > > /**