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Commit 12119151 authored by Bryan O'Donoghue's avatar Bryan O'Donoghue Committed by Greg Kroah-Hartman
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greybus: timesync: Enforce TimeSync locks as subordinate to Interface locks 



gb_timesync_svc_teardown() is called from gb_timesync_svc_del() and issues a
command to a remote Interface to switch off its timers. The lock ordering
is TimeSync => Interface in this case. However gb_module_del() takes an
Interface lock then calls gb_interface_del() => gb_timesync_svc_del() in
this case the lock ordering is Interface => TimeSync.

This patch fixes by removing the taking of the Interface mutex in
gb_interface_timesync_do_something(). If an Interface is present in the
TimeSync linked-list - it is by definition intf->enabled.

Reported-by: default avatarRui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: default avatarBryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
parent 5e2b6391

drivers/staging/greybus/interface.c

+9 −41
Original line number Diff line number Diff line
@@ -872,60 +872,28 @@ void gb_interface_disable(struct gb_interface *intf) 
	intf->enabled = false;

}



/*

 * Enable TimeSync on an Interface control connection.

 *

 * Locking: Takes and releases the interface mutex.

 */

/* Enable TimeSync on an Interface control connection. */

int gb_interface_timesync_enable(struct gb_interface *intf, u8 count,

				 u64 frame_time, u32 strobe_delay, u32 refclk)

{

	int ret = -ENODEV;



	mutex_lock(&intf->mutex);

	if (intf->enabled) {

		ret = gb_control_timesync_enable(intf->control, count,

	return gb_control_timesync_enable(intf->control, count,

					  frame_time, strobe_delay,

					  refclk);

}

	mutex_unlock(&intf->mutex);

	return ret;

}



/*

 * Disable TimeSync on an Interface control connection.

 *

 * Locking: Takes and releases the interface mutex.

 */

/* Disable TimeSync on an Interface control connection. */

int gb_interface_timesync_disable(struct gb_interface *intf)

{

	int ret = -ENODEV;



	mutex_lock(&intf->mutex);

	if (intf->enabled)

		ret = gb_control_timesync_disable(intf->control);

	mutex_unlock(&intf->mutex);

	return ret;

	return gb_control_timesync_disable(intf->control);

}



/*

 * Transmit the Authoritative FrameTime via an Interface control connection.

 *

 * Locking: Takes and releases the interface mutex.

 */

/* Transmit the Authoritative FrameTime via an Interface control connection. */

int gb_interface_timesync_authoritative(struct gb_interface *intf,

					u64 *frame_time)

{

	int ret = -ENODEV;



	mutex_lock(&intf->mutex);

	if (intf->enabled) {

		ret = gb_control_timesync_authoritative(intf->control,

	return gb_control_timesync_authoritative(intf->control,

						frame_time);

}

	mutex_unlock(&intf->mutex);

	return ret;

}



/* Register an interface. */

int gb_interface_add(struct gb_interface *intf)