Make sure that the zone write pointer offset array is allocated with a
vmalloc in dm_zone_revalidate_cb() by passing GFP_KERNEL gfp flag to
kvcalloc(). However, since we do not want to trigger IOs while
revalidating zones, change dm_revalidate_zones() to have the zone scan
done in GFP_NOIO context using memalloc_noio_save/restore calls.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: bb37d77239af ("dm: introduce zone append emulation") Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>