ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE

ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE

BugLink: http://bugs.launchpad.net/bugs/1752119
commit 6e6e41c3112276288ccaf80c70916779b84bb276 upstream.

To avoid slab to warn about exceeded size, fail early if queue
occupies more than KMALLOC_MAX_SIZE.

Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com
Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>