Paul McKenney pointed out that reading the truncate sequence number in
do_no_page might not be entirely safe if the ->nopage callout takes no
locks.  The simple solution is to move the read before the unlock of
page_table_lock.  Here's a patch that does it.

Dave McCracken

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Dave McCracken          IBM Linux Base Kernel Team      1-512-838-3059
dmccr@us.ibm.com                                        T/L   678-3059