get_user_pages requires caller to hold a read lock on mmap_sem.
Signed-off-by: NJay Cornwall <jay.cornwall@amd.com>
Signed-off-by: NSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: NJoerg Roedel <joro@8bytes.org>