Use GFP_NOIO for memory allocations in the I/O path.  Other memory
allocations in the initialization path can use GFP_KERNEL.
Reported-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>