zpool driver adds a flag to indicate whether the zpool driver can enter an
atomic context after mapping.  This patch sets it true for z3fold and
zbud.

Link: https://lkml.kernel.org/r/1611035683-12732-3-git-send-email-tiantao6@hisilicon.comSigned-off-by: Tian Tao <tiantao6@hisilicon.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Mike Galbraith <efault@gmx.de>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>