This patch (as1522) adds two new routines to the usb-serial core, for
registering and unregistering serial drivers. Instead of registering
the usb_driver and usb_serial_drivers separately, with error checking
for each one, the drivers can all be registered and unregistered by a
single function call. This reduces duplicated code.
More importantly, the new core routines change the order in which the
drivers are registered. Currently the usb-serial drivers are all
registered first and the usb_driver is done last, which leaves a
window for problems. A udev script may quickly add a new dynamic-ID
for a usb-serial driver, causing the corresponding usb_driver to be
probed. If the usb_driver hasn't been registered yet then an oops
will occur.
The new routine prevents such problems by registering the usb_driver
first. To insure that it gets probed properly for already-attached
serial devices, we call driver_attach() after all the usb-serial
drivers have been registered.
Along with adding the new routines, the patch modifies the "generic"
serial driver to use them. Further patches will similarly modify all
the other in-tree USB serial drivers.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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