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authorPetr Mladek <pmladek@suse.cz>2014-09-19 17:32:24 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-09-23 22:33:19 -0700
commit638139eb95d2d241781330a321e88c8dafe46078 (patch)
treeccb7df7cabe74a62e0bd707f7700f0e4efb5516e /drivers/usb
parent37ebb54915dc42944f6ae92fe53b9531c3903801 (diff)
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>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/core/hub.c9
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;