[PATCH 1/2] Fix Use hashtable to record udev path

[Zhang, Zhenhua]

Hi,

Zhang, Zhenhua wrote:
> Sometimes, Udev device 'remove' event could not report correct
> parent node of current udev_device. Current code replies on
> the devpath attached on the parent node to find modem and then
> remove it.
> 
> This fix is to change the way to store the devpath info into a
> hashtable. So that we search hashtable to get devpath and
> remove the modem.
> ---

It's a proposed patch to fix Meego bug #395 [1].

oFono relies on udev to report device remove event. The devpath info of the modem is stored in the parent node of tty port. In below case, we try to find this parent node of /dev/ttyACM0. The expected path of node is ".../usb1/1-4", which is modem device itself. On Netbook, however, it returns ".../usb1" sometimes. In such case, we could not find the correct devpath and modem so that modem was never removed.

My idea is to use a hashtable to store the mapping between tty path and modem path. So that we could find the modem path without depending on udev_device_get_parent() in remove_modem.

Wrong log is listed below. The expected path is '/devices/pci0000:00/0000:00:1d.7/usb1/1-4/', but it returns '.../0000:00:1d.7/usb1', which is Linux USB host controller.

Wrong log 1:
	remove_modem() device 0x9223820
	path #0 /devices/pci0000:00/0000:00:1d.7/usb1/1-4/1-4:1.1/tty/ttyACM0
	path #1 /devices/pci0000:00/0000:00:1d.7/usb1
	path #2 /devices/pci0000:00/0000:00:1d.7/usb1
	path #3 /devices/pci0000:00/0000:00:1d.7
	path #4 /devices/pci0000:00
	remove_modem() device 0x9222628
	path #0 /devices/pci0000:00/0000:00:1d.7/usb1/1-4/1-4:1.3/tty/ttyACM1
	path #1 /devices/pci0000:00/0000:00:1d.7/usb1
	path #2 /devices/pci0000:00/0000:00:1d.7/usb1
	path #3 /devices/pci0000:00/0000:00:1d.7
	path #4 /devices/pci0000:00
	remove_modem() device 0x92233a8
	path #0 /devices/pci0000:00/0000:00:1d.7/usb1/1-4/1-4:1.7/net/wwan0
	path #1 /devices/pci0000:00/0000:00:1d.7/usb1
	path #2 /devices/pci0000:00/0000:00:1d.7/usb1
	path #3 /devices/pci0000:00/0000:00:1d.7
	path #4 /devices/pci0000:00
	remove_modem() device 0x9224520
	path #0 /devices/pci0000:00/0000:00:1d.7/usb1/1-4/1-4:1.9/tty/ttyACM2
	path #1 /devices/pci0000:00/0000:00:1d.7/usb1
	path #2 /devices/pci0000:00/0000:00:1d.7/usb1
	path #3 /devices/pci0000:00/0000:00:1d.7
	path #4 /devices/pci0000:00

Wrong log 2:
	remove_modem() device 0x9226398
	path #0 /1-4:1.1/tty/ttyACM0
	remove_modem() device 0x9226398
	path #0 /1-4:1.3/tty/ttyACM1
	remove_modem() device 0x9226398
	path #0 /devices/pci0000:00/0000:00:1d.7/usb1/1-4/1-4:1.9/tty/ttyACM2
	path #1 /devices/pci0000:00/0000:00:1d.7/usb1
	path #2 /devices/pci0000:00/0000:00:1d.7/usb1
	path #3 /devices/pci0000:00/0000:00:1d.7
	path #4 /devices/pci0000:00
	remove_modem() device 0x9224880
	path #0 /devices/pci0000:00/0000:00:1d.7/usb1/1-4/1-4:1.7/net/wwan0
	path #1 /devices/pci0000:00/0000:00:1d.7/usb1
	path #2 /devices/pci0000:00/0000:00:1d.7/usb1
	path #3 /devices/pci0000:00/0000:00:1d.7
	path #4 /devices/pci0000:00

[1] http://bugs.meego.com/show_bug.cgi?id=395

Regards,
Zhenhua

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