Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
IronPort-SDR: TrQOkzDuolXJUMTPo2K5HXoHg/ggo3T0ufETrbzTLZWL9eor9HDoWJ13NLIxasnRSejJg9I0w4
 O0aBChzSre4Q==
From:   Paul Durrant <pdurrant@amazon.com>
To:     <linux-kernel@vger.kernel.org>, <xen-devel@lists.xenproject.org>
CC:     Paul Durrant <pdurrant@amazon.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Juergen Gross <jgross@suse.com>,
        "Stefano Stabellini" <sstabellini@kernel.org>
Subject: [PATCH 2/4] xenbus: limit when state is forced to closed
Date:   Thu, 5 Dec 2019 14:01:21 +0000
Message-ID: <20191205140123.3817-3-pdurrant@amazon.com>
In-Reply-To: <20191205140123.3817-1-pdurrant@amazon.com>
References: <20191205140123.3817-1-pdurrant@amazon.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Only force state to closed 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.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
---
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
---
 drivers/xen/xenbus/xenbus_probe.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index a10311c348b9..c54a53da0106 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);
@@ -264,6 +263,7 @@ int xenbus_dev_remove(struct device *_dev)
 {
 	struct xenbus_device *dev = to_xenbus_device(_dev);
 	struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
+	enum xenbus_state state;
 
 	DPRINTK("%s", dev->nodename);
 
@@ -276,7 +276,14 @@ int xenbus_dev_remove(struct device *_dev)
 
 	free_otherend_details(dev);
 
-	xenbus_switch_state(dev, XenbusStateClosed);
+	/*
+	 * If the toolstack had force the device state to closing then set
+	 * the state to closed now to allow it to be cleaned up.
+	 */
+	state = xenbus_read_driver_state(dev->nodename);
+	if (state == XenbusStateClosing)
+		xenbus_switch_state(dev, XenbusStateClosed);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
-- 
2.20.1