From patchwork Tue Nov 22 15:53:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ira Weiny X-Patchwork-Id: 13052515 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 23458C433FE for ; Tue, 22 Nov 2022 15:53:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232517AbiKVPxb (ORCPT ); Tue, 22 Nov 2022 10:53:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233626AbiKVPx3 (ORCPT ); Tue, 22 Nov 2022 10:53:29 -0500 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BB3E48779; Tue, 22 Nov 2022 07:53:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1669132408; x=1700668408; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=YUJ7EdYfUOaMRwptVpLuSUm6x5AoT6ZUjcLdR6MstiY=; b=kvgOBGhVXFJVFRcBO54KKqM/RGEUdFFFFxBpezx7FOXgnyg0ew0q/Qp9 2sV586QTDlHRV9xxYAgBIcnMWV5hAI3B1O+Y9wWzADOJzQTgnNhHDyA/u 3lZNVZYDN9bhsI5u31pP64xXb82ypEgm/C+n/hwE9IJBtUv3uy1lYaDVy axBlJkSjNqoBGXFQ0HERl10eSrBlxhe+SYba8hmnUpf5XCEnuhKE1QBWd fm+QnllWbcCIoJjgIz1GUJJ8aMZdiVm3VzYj1P3hCRSQaxWVljYVJqpHm TczU7eBHyCAseqmM0kEamdoyUD4srK8omwMstoGgvIk+nrZetiqzf9jrx Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10539"; a="313877730" X-IronPort-AV: E=Sophos;i="5.96,184,1665471600"; d="scan'208";a="313877730" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Nov 2022 07:53:28 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10539"; a="816142053" X-IronPort-AV: E=Sophos;i="5.96,184,1665471600"; d="scan'208";a="816142053" Received: from iweiny-mobl.amr.corp.intel.com (HELO localhost) ([10.209.130.75]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Nov 2022 07:53:27 -0800 From: ira.weiny@intel.com To: Dan Williams , Bjorn Helgaas Cc: Ira Weiny , Lukas Wunner , Alison Schofield , Vishal Verma , Jonathan Cameron , Gregory Price , "Li, Ming" , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org Subject: [PATCH V2 1/2] PCI/DOE: Remove the pci_doe_flush_mb() call Date: Tue, 22 Nov 2022 07:53:23 -0800 Message-Id: <20221122155324.1878416-2-ira.weiny@intel.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20221122155324.1878416-1-ira.weiny@intel.com> References: <20221122155324.1878416-1-ira.weiny@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Ira Weiny Each struct doe_mb is managed as part of the PCI device. They can't go away as long as the PCI device exists. pci_doe_flush_mb() was set up to flush the workqueue and prevent any further submissions to the mailboxes when the PCI device goes away. Unfortunately, this was fundamentally flawed. There was no guarantee that a struct doe_mb remained after pci_doe_flush_mb() returned. Therefore, the doe_mb state could be invalid when those threads waiting on the workqueue were flushed. Fortunately the current code is safe because all callers make a synchronous call to pci_doe_submit_task() and maintain a reference on the PCI device. For these reasons, pci_doe_flush_mb() will never be called while tasks are being processed and there is no use for it. Remove the dead code around pci_doe_flush_mb(). Signed-off-by: Ira Weiny --- drivers/pci/doe.c | 48 ++++------------------------------------------- 1 file changed, 4 insertions(+), 44 deletions(-) diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c index e402f05068a5..260313e9052e 100644 --- a/drivers/pci/doe.c +++ b/drivers/pci/doe.c @@ -24,10 +24,9 @@ /* Timeout of 1 second from 6.30.2 Operation, PCI Spec r6.0 */ #define PCI_DOE_TIMEOUT HZ -#define PCI_DOE_POLL_INTERVAL (PCI_DOE_TIMEOUT / 128) +#define PCI_DOE_POLL_INTERVAL 8 -#define PCI_DOE_FLAG_CANCEL 0 -#define PCI_DOE_FLAG_DEAD 1 +#define PCI_DOE_FLAG_DEAD 0 /** * struct pci_doe_mb - State for a single DOE mailbox @@ -53,15 +52,6 @@ struct pci_doe_mb { unsigned long flags; }; -static int pci_doe_wait(struct pci_doe_mb *doe_mb, unsigned long timeout) -{ - if (wait_event_timeout(doe_mb->wq, - test_bit(PCI_DOE_FLAG_CANCEL, &doe_mb->flags), - timeout)) - return -EIO; - return 0; -} - static void pci_doe_write_ctrl(struct pci_doe_mb *doe_mb, u32 val) { struct pci_dev *pdev = doe_mb->pdev; @@ -82,12 +72,9 @@ static int pci_doe_abort(struct pci_doe_mb *doe_mb) pci_doe_write_ctrl(doe_mb, PCI_DOE_CTRL_ABORT); do { - int rc; u32 val; - rc = pci_doe_wait(doe_mb, PCI_DOE_POLL_INTERVAL); - if (rc) - return rc; + msleep_interruptible(PCI_DOE_POLL_INTERVAL); pci_read_config_dword(pdev, offset + PCI_DOE_STATUS, &val); /* Abort success! */ @@ -278,11 +265,7 @@ static void doe_statemachine_work(struct work_struct *work) signal_task_abort(task, -EIO); return; } - rc = pci_doe_wait(doe_mb, PCI_DOE_POLL_INTERVAL); - if (rc) { - signal_task_abort(task, rc); - return; - } + msleep_interruptible(PCI_DOE_POLL_INTERVAL); goto retry_resp; } @@ -383,21 +366,6 @@ static void pci_doe_destroy_workqueue(void *mb) destroy_workqueue(doe_mb->work_queue); } -static void pci_doe_flush_mb(void *mb) -{ - struct pci_doe_mb *doe_mb = mb; - - /* Stop all pending work items from starting */ - set_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags); - - /* Cancel an in progress work item, if necessary */ - set_bit(PCI_DOE_FLAG_CANCEL, &doe_mb->flags); - wake_up(&doe_mb->wq); - - /* Flush all work items */ - flush_workqueue(doe_mb->work_queue); -} - /** * pcim_doe_create_mb() - Create a DOE mailbox object * @@ -450,14 +418,6 @@ struct pci_doe_mb *pcim_doe_create_mb(struct pci_dev *pdev, u16 cap_offset) return ERR_PTR(rc); } - /* - * The state machine and the mailbox should be in sync now; - * Set up mailbox flush prior to using the mailbox to query protocols. - */ - rc = devm_add_action_or_reset(dev, pci_doe_flush_mb, doe_mb); - if (rc) - return ERR_PTR(rc); - rc = pci_doe_cache_protocols(doe_mb); if (rc) { pci_err(pdev, "[%x] failed to cache protocols : %d\n",