From patchwork Thu Oct 6 13:49:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Manivannan Sadhasivam X-Patchwork-Id: 13000383 X-Patchwork-Delegate: lorenzo.pieralisi@arm.com 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 59C08C433FE for ; Thu, 6 Oct 2022 13:50:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231576AbiJFNuR (ORCPT ); Thu, 6 Oct 2022 09:50:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231634AbiJFNuM (ORCPT ); Thu, 6 Oct 2022 09:50:12 -0400 Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8749C45F49 for ; Thu, 6 Oct 2022 06:50:00 -0700 (PDT) Received: by mail-pl1-x629.google.com with SMTP id l4so1760231plb.8 for ; Thu, 06 Oct 2022 06:50:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date; bh=b98/tdiTwcvqr19Hh3b2b2FTs+schd1Q4q9W1vv+i7w=; b=f3lE3n1jFX5eANT3457wStFC3x8NgEWMerXa7SYsS4AMyPnchWeOmot0g5vwPiv7L4 fW/GZheMjMzyAB2CJjKXehrMRRdBFEpBpHdgWpWcfK9aKcLCTrXWFA3vCvShmnv1mLwD MjPE5DlX+qXwxPMjeOe4iEw6zecAQlA9csayKh8ddVPAXmVrKyCNxqPPP+h21TRSJQj1 OBWFt3BUrldpwTkbV8S87/iPicmgvPcnhCU7V+nWUFLHxfiA0obg2DyU9c3Y/uSONYRT j5HwA0BPZ7qYXgdzqdZW9NFCvTD+W0cWNuSQ+bfCFM/Vv59+yluuLCJTjtZafKpqTx4L iFFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date; bh=b98/tdiTwcvqr19Hh3b2b2FTs+schd1Q4q9W1vv+i7w=; b=VQVfcr4J6rSZ0RZuHLPOQmnnOj8RC3YfAsLJjYfbnV5WflTwzDh+44/ngHZaKMZhGP 76yjtnckBIuP1siUDGJn+QFScvFjdCE++L9cB9GLrl97ib/fG3k5sQOjIPrn/lFhdDPi vET6XCd6pHUlYBYr6t8S7ZE1Vs4Z/QgnlzeT9wMzEYpWtGP7Yqxq6F46UqPZsk0Hz+dL lzAd24t6r0uWZVRupGyNPbmZpuNALETHlwI/+p5p7lkwueO84bHCKKeUlLqxwaHAGf5m hulcv7w4A7MzClY4pM7CtcqQtTyT56B5vFaNRjnVZD9T+shiPERYaaJ1KxueGDbp+WJd 1K/g== X-Gm-Message-State: ACrzQf3eaV3MlxD9+rzrDFvwc7ocTkE5gxMGyyf+4yJ3A/qNOUkunN9x qM6nhyW8BBbNfmEeiU33QTO9 X-Google-Smtp-Source: AMsMyM4P7ZuRzbrkXhZRWHNPuzPp2qehAKeCoVS8zM5dgefeOtWm2noYpuK7VzCYrXRQHqTic/7a8Q== X-Received: by 2002:a17:90a:cd02:b0:205:efbd:6f60 with SMTP id d2-20020a17090acd0200b00205efbd6f60mr10800376pju.111.1665064199534; Thu, 06 Oct 2022 06:49:59 -0700 (PDT) Received: from localhost.localdomain ([220.158.158.220]) by smtp.gmail.com with ESMTPSA id k25-20020a635a59000000b00434760ee36asm1874053pgm.16.2022.10.06.06.49.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Oct 2022 06:49:58 -0700 (PDT) From: Manivannan Sadhasivam To: 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, Manivannan Sadhasivam Subject: [PATCH v3 4/5] PCI: endpoint: Use callback mechanism for passing events from EPC to EPF Date: Thu, 6 Oct 2022 19:19:26 +0530 Message-Id: <20221006134927.41437-5-manivannan.sadhasivam@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221006134927.41437-1-manivannan.sadhasivam@linaro.org> References: <20221006134927.41437-1-manivannan.sadhasivam@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org 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 --- 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..ba54f17ae06f 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->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; }; /**