linux-kernel - [PATCH v2] Do not disable driver and bus shutdown hook when class shutdown hook is set.

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Message-Id: <20170811134443.770-1-msuchanek@suse.de>
Date:   Fri, 11 Aug 2017 15:44:43 +0200
From:   Michal Suchanek <msuchanek@...e.de>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Peter Huewe <peterhuewe@....de>,
        Marcel Selhorst <tpmdd@...horst.net>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        "David S. Miller" <davem@...emloft.net>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Phil Sutter <phil@....cc>, Josh Zimmerman <joshz@...gle.com>,
        Michal Suchanek <msuchanek@...e.de>,
        Madalin Bucur <madalin.bucur@....com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Ludovic Desroches <ludovic.desroches@...inux.fr>,
        linux-kernel@...r.kernel.org, tpmdd-devel@...ts.sourceforge.net
Subject: [PATCH v2] Do not disable driver and bus shutdown hook when class shutdown hook is set.

As seen from the implementation of the single class shutdown hook this
is not very sound design.

Rename the class shutdown hook to shutdown_pre to make it clear it runs
before the driver shutdown hook.

Signed-off-by: Michal Suchanek <msuchanek@...e.de>
---
v2: rename class shutdown member to shutdown_pre
---
 drivers/base/core.c         |  9 +++++----
 drivers/char/tpm/tpm-chip.c | 11 ++---------
 include/linux/device.h      |  4 ++--
 3 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 755451f684bc..13e7c41fd417 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2664,11 +2664,12 @@ void device_shutdown(void)
 		pm_runtime_get_noresume(dev);
 		pm_runtime_barrier(dev);
 
-		if (dev->class && dev->class->shutdown) {
+		if (dev->class && dev->class->shutdown_pre) {
 			if (initcall_debug)
-				dev_info(dev, "shutdown\n");
-			dev->class->shutdown(dev);
-		} else if (dev->bus && dev->bus->shutdown) {
+				dev_info(dev, "shutdown_pre\n");
+			dev->class->shutdown_pre(dev);
+		}
+		if (dev->bus && dev->bus->shutdown) {
 			if (initcall_debug)
 				dev_info(dev, "shutdown\n");
 			dev->bus->shutdown(dev);
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 67ec9d3d04f5..0eca20c5a80c 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -164,14 +164,7 @@ static int tpm_class_shutdown(struct device *dev)
 		chip->ops = NULL;
 		up_write(&chip->ops_sem);
 	}
-	/* Allow bus- and device-specific code to run. Note: since chip->ops
-	 * is NULL, more-specific shutdown code will not be able to issue TPM
-	 * commands.
-	 */
-	if (dev->bus && dev->bus->shutdown)
-		dev->bus->shutdown(dev);
-	else if (dev->driver && dev->driver->shutdown)
-		dev->driver->shutdown(dev);
+
 	return 0;
 }
 
@@ -214,7 +207,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 	device_initialize(&chip->devs);
 
 	chip->dev.class = tpm_class;
-	chip->dev.class->shutdown = tpm_class_shutdown;
+	chip->dev.class->shutdown_pre = tpm_class_shutdown;
 	chip->dev.release = tpm_dev_release;
 	chip->dev.parent = pdev;
 	chip->dev.groups = chip->groups;
diff --git a/include/linux/device.h b/include/linux/device.h
index beabdbc08420..649b1b72c76a 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -375,7 +375,7 @@ int subsys_virtual_register(struct bus_type *subsys,
  * @suspend:	Used to put the device to sleep mode, usually to a low power
  *		state.
  * @resume:	Used to bring the device from the sleep mode.
- * @shutdown:	Called at shut-down time to quiesce the device.
+ * @shutdown_pre: Called at shut-down time before driver shutdown.
  * @ns_type:	Callbacks so sysfs can detemine namespaces.
  * @namespace:	Namespace of the device belongs to this class.
  * @pm:		The default device power management operations of this class.
@@ -404,7 +404,7 @@ struct class {
 
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
-	int (*shutdown)(struct device *dev);
+	int (*shutdown_pre)(struct device *dev);
 
 	const struct kobj_ns_type_operations *ns_type;
 	const void *(*namespace)(struct device *dev);
-- 
2.10.2