The block layer uses an unsigned short for max_segments. The way we
calculate the value for NVMe tends to generate very large 32-bit values,
which after integer truncation may lead to a zero value instead of
the desired outcome.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reported-by: Jeff Lien <Jeff.Lien@hgst.com> Tested-by: Jeff Lien <Jeff.Lien@hgst.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>