[ Upstream commit aa5334c4f3014940f11bf876e919c956abef4089 ]

Passing the parameter "num_tgts=-1" will start an infinite loop that
exhausts the system memory

Link: https://lore.kernel.org/r/20191115163727.24626-1-mlombard@redhat.comSigned-off-by: NMaurizio Lombardi <mlombard@redhat.com>
Acked-by: NDouglas Gilbert <dgilbert@interlog.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>