h will no longer be blocked. One
problem with this approach is that usb-stor-scan has a delay to
wait for devices to settle (which is currently the only point where
it can freeze). To work around this we can request that the freezer
send a fake signal when freezing, then use interruptible sleep to
wake the thread early when freezing happens.

To make this happen, the following changes are made to
usb-stor-scan:

 * Use set_freezable_with_signal() instead of set_freezable() to
   request a fake signal when freezing

 * Use wait_event_interruptible_timeout() instead of
   wait_event_freezable_timeout() to avoid freezing

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>