Don't lock a parent device unless it is needed in device_shutdown. This is in preparation for making device shutdown asynchronous, when it will be needed to allow children of a common parent to shut down simultaneously.
And only acquire a reference to the parent device if the parent is to be locked. Signed-off-by: Stuart Hayes <[email protected]> Signed-off-by: David Jeffery <[email protected]> Tested-by: Laurence Oberman <[email protected]> Tested-by: Tarun Sahu <[email protected]> Reviewed-by: Martin K. Petersen <[email protected]> Reviewed-by: Pasha Tatashin <[email protected]> --- drivers/base/core.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 127432248165..6e2c37115bc1 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4795,13 +4795,8 @@ int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid) return error; } -static void shutdown_one_device(struct device *dev) +static void __shutdown_one_device(struct device *dev) { - struct device *parent = dev->parent; - - /* hold lock to avoid race with probe/release */ - if (parent) - device_lock(parent); device_lock(dev); /* Don't allow any more runtime suspends */ @@ -4824,10 +4819,23 @@ static void shutdown_one_device(struct device *dev) } device_unlock(dev); - if (parent) +} + +static void shutdown_one_device(struct device *dev) +{ + struct device *parent; + + /* hold lock if needed to avoid race with probe/release */ + if (dev->bus && dev->bus->need_parent_lock && + (parent = get_device(dev->parent))) { + device_lock(parent); + __shutdown_one_device(dev); device_unlock(parent); + put_device(parent); + } else { + __shutdown_one_device(dev); + } - put_device(parent); put_device(dev); } @@ -4853,12 +4861,6 @@ void device_shutdown(void) dev = list_entry(devices_kset->list.prev, struct device, kobj.entry); - /* - * hold reference count of device's parent to - * prevent it from being freed because parent's - * lock is to be held - */ - get_device(dev->parent); get_device(dev); /* * Make sure the device is off the kset list, in the -- 2.53.0
