Commit c37d721c authored Nov 28, 2018 by Alexander Duyck Committed by Greg Kroah-Hartman Dec 06, 2018

driver core: Move async_synchronize_full call

Move the async_synchronize_full call out of __device_release_driver and
into driver_detach.

The idea behind this is that the async_synchronize_full call will only
guarantee that any existing async operations are flushed. This doesn't do
anything to guarantee that a hotplug event that may occur while we are
doing the release of the driver will not be asynchronously scheduled.

By moving this into the driver_detach path we can avoid potential deadlocks
as we aren't holding the device lock at this point and we should not have
the driver we want to flush loaded so the flush will take care of any
asynchronous events the driver we are detaching might have scheduled.

Fixes: 765230b5 ("driver-core: add asynchronous probing support for drivers")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 99fef587

drivers/base/dd.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -931,9 +931,6 @@ static void __device_release_driver(struct device dev, struct device parent)

		drv = dev->driver;
		if (drv) {
		if (driver_allows_async_probing(drv))
		async_synchronize_full();

		while (device_links_busy(dev)) {
		device_unlock(dev);
		if (parent)
		@@ -1039,6 +1036,9 @@ void driver_detach(struct device_driver *drv)
		struct device_private *dev_prv;
		struct device *dev;

		if (driver_allows_async_probing(drv))
		async_synchronize_full();

		for (;;) {
		spin_lock(&drv->p->klist_devices.k_lock);
		if (list_empty(&drv->p->klist_devices.k_list)) {

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