[2.6.20.17 review 14/58] USB: fix warning caused by autosuspend counter going negative

Willy Tarreau
2007-08-22T09:15:55Z

[-- Attachment #1: 0014-USB-fix-warning-caused-by-autosuspend-counter-going.patch --]
[-- Type: text/plain, Size: 1602 bytes --]

This patch (as937) fixes a minor bug in the autosuspend usage-counting
code. Each hub's usage counter keeps track of the number of
unsuspended children. However the current driver increments the
counter after registering a new child, by which time the child may
already have been suspended and caused the counter to go negative.
The obvious solution is to increment the counter before registering
the child.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
drivers/usb/core/hub.c | 10 ++++++----
1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 8ddeed3..d5890d5 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1356,6 +1356,10 @@ static int __usb_new_device(void *void_data)
}
#endif

+ /* Increment the parent's count of unsuspended children */
+ if (udev->parent)
+ usb_autoresume_device(udev->parent);
+
/* Register the device. The device driver is responsible
* for adding the device files to usbfs and sysfs and for
* configuring the device.
@@ -1363,13 +1367,11 @@ static int __usb_new_device(void *void_data)
err = device_add (&udev->dev);
if (err) {
dev_err(&udev->dev, "can't device_add, error %d
", err);
+ if (udev->parent)
+ usb_autosuspend_device(udev->parent);
goto fail;
}

- /* Increment the parent's count of unsuspended children */
- if (udev->parent)
- usb_autoresume_device(udev->parent);
-
exit:
module_put(THIS_MODULE);
return err;
--
1.5.2.5

--