diff options
| author | Petr Mladek <pmladek@suse.cz> | 2014-09-19 17:32:24 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-09-23 22:33:19 -0700 |
| commit | 638139eb95d2d241781330a321e88c8dafe46078 (patch) | |
| tree | ccb7df7cabe74a62e0bd707f7700f0e4efb5516e | |
| parent | 37ebb54915dc42944f6ae92fe53b9531c3903801 (diff) | |
| download | blackbird-op-linux-638139eb95d2d241781330a321e88c8dafe46078.tar.gz blackbird-op-linux-638139eb95d2d241781330a321e88c8dafe46078.zip | |
usb: hub: allow to process more usb hub events in parallel
It seems that only choose_devnum() was not ready to process more hub
events at the same time.
All should be fine if we take bus->usb_address0_mutex there. It will
make sure that more devnums will not be chosen for the given bus and
the related devices at the same time.
Signed-off-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/core/hub.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 12a4c67667b1..374b3f93071c 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2045,7 +2045,8 @@ static void choose_devnum(struct usb_device *udev) int devnum; struct usb_bus *bus = udev->bus; - /* If hub_wq ever becomes multithreaded, this will need a lock */ + /* be safe when more hub events are proceed in parallel */ + mutex_lock(&bus->usb_address0_mutex); if (udev->wusb) { devnum = udev->portnum + 1; BUG_ON(test_bit(devnum, bus->devmap.devicemap)); @@ -2063,6 +2064,7 @@ static void choose_devnum(struct usb_device *udev) set_bit(devnum, bus->devmap.devicemap); udev->devnum = devnum; } + mutex_unlock(&bus->usb_address0_mutex); } static void release_devnum(struct usb_device *udev) @@ -5164,11 +5166,8 @@ int usb_hub_init(void) * USB-PERSIST port handover. Otherwise it might see that a full-speed * device was gone before the EHCI controller had handed its port * over to the companion full-speed controller. - * - * Also we use ordered workqueue because the code is not ready - * for parallel execution of hub events, see choose_devnum(). */ - hub_wq = alloc_ordered_workqueue("usb_hub_wq", WQ_FREEZABLE); + hub_wq = alloc_workqueue("usb_hub_wq", WQ_FREEZABLE, 0); if (hub_wq) return 0; |
