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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 67731C43603 for ; Tue, 10 Dec 2019 11:34:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B0C520663 for ; Tue, 10 Dec 2019 11:34:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="rfeQrXTt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727348AbfLJLec (ORCPT ); Tue, 10 Dec 2019 06:34:32 -0500 Received: from smtp-fw-9102.amazon.com ([207.171.184.29]:62268 "EHLO smtp-fw-9102.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727211AbfLJLec (ORCPT ); Tue, 10 Dec 2019 06:34:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1575977672; x=1607513672; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=nJN0wSFtdOZDYjIZyP04UHN4GCv/sSLr82yiruvNA8s=; b=rfeQrXTt8Adg1cg1n56VnPS2hd3iQPCLamyav/J0APYaE58oqLLcL3bU NOyhYqjDCEx16kbmNakQLEbPTcf3Enggb1abxs+lfbfcDWPIvhHLHgZtb GhCvhmUoXS+0rz6i/DZsrsmpuo5xoUwP+hev6uWS6YxQxJ9Xn2SqfAJ6U E=; IronPort-SDR: v9HAsxUvYmEiTpVmKIHL6RlIhHRXGh0KROqBNNZAN+n39/I6tRV+5fSJgtDts5HUSYayq9NVAY 7jAdk/ztpExw== X-IronPort-AV: E=Sophos;i="5.69,299,1571702400"; d="scan'208";a="12635017" Received: from sea32-co-svc-lb4-vlan3.sea.corp.amazon.com (HELO email-inbound-relay-2c-4e7c8266.us-west-2.amazon.com) ([10.47.23.38]) by smtp-border-fw-out-9102.sea19.amazon.com with ESMTP; 10 Dec 2019 11:34:13 +0000 Received: from EX13MTAUEA001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2c-4e7c8266.us-west-2.amazon.com (Postfix) with ESMTPS id 05FA3A1F60; Tue, 10 Dec 2019 11:34:10 +0000 (UTC) Received: from EX13D32EUB002.ant.amazon.com (10.43.166.114) by EX13MTAUEA001.ant.amazon.com (10.43.61.82) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Tue, 10 Dec 2019 11:34:10 +0000 Received: from EX13MTAUEE001.ant.amazon.com (10.43.62.200) by EX13D32EUB002.ant.amazon.com (10.43.166.114) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Tue, 10 Dec 2019 11:34:09 +0000 Received: from u2f063a87eabd5f.cbg10.amazon.com (10.125.106.135) by mail-relay.amazon.com (10.43.62.226) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Tue, 10 Dec 2019 11:34:08 +0000 From: Paul Durrant To: , CC: Paul Durrant , Boris Ostrovsky , Juergen Gross , "Stefano Stabellini" Subject: [PATCH v2 2/4] xenbus: limit when state is forced to closed Date: Tue, 10 Dec 2019 11:33:45 +0000 Message-ID: <20191210113347.3404-3-pdurrant@amazon.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191210113347.3404-1-pdurrant@amazon.com> References: <20191210113347.3404-1-pdurrant@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If a driver probe() fails then leave the xenstore state alone. There is no reason to modify it as the failure may be due to transient resource allocation issues and hence a subsequent probe() may succeed. If the driver supports re-binding then only force state to closed during remove() only in the case when the toolstack may need to clean up. This can be detected by checking whether the state in xenstore has been set to closing prior to device removal. NOTE: Re-bind support is indicated by new boolean in struct xenbus_driver, which defaults to false. Subsequent patches will add support to some backend drivers. Signed-off-by: Paul Durrant --- Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Stefano Stabellini v2: - Introduce the 'allow_rebind' flag - Expand the commit comment --- drivers/xen/xenbus/xenbus_probe.c | 12 ++++++++++-- include/xen/xenbus.h | 1 + 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index a10311c348b9..9303ff35b2bd 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -255,7 +255,6 @@ int xenbus_dev_probe(struct device *_dev) module_put(drv->driver.owner); fail: xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename); - xenbus_switch_state(dev, XenbusStateClosed); return err; } EXPORT_SYMBOL_GPL(xenbus_dev_probe); @@ -276,7 +275,16 @@ int xenbus_dev_remove(struct device *_dev) free_otherend_details(dev); - xenbus_switch_state(dev, XenbusStateClosed); + /* + * If the toolstack has forced the device state to closing then set + * the state to closed now to allow it to be cleaned up. + * Similarly, if the driver does not support re-bind, set the + * closed. + */ + if (!drv->allow_rebind || + xenbus_read_driver_state(dev->nodename) == XenbusStateClosing) + xenbus_switch_state(dev, XenbusStateClosed); + return 0; } EXPORT_SYMBOL_GPL(xenbus_dev_remove); diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h index 869c816d5f8c..24228a102141 100644 --- a/include/xen/xenbus.h +++ b/include/xen/xenbus.h @@ -93,6 +93,7 @@ struct xenbus_device_id struct xenbus_driver { const char *name; /* defaults to ids[0].devicetype */ const struct xenbus_device_id *ids; + bool allow_rebind; /* avoid setting xenstore closed during remove */ int (*probe)(struct xenbus_device *dev, const struct xenbus_device_id *id); void (*otherend_changed)(struct xenbus_device *dev, -- 2.20.1