[BUG] nvme/pci: nvme_map_cmb triggers WARN_ON in __add_pages when CMBSZ.SZ is zero

[Keith Busch]

On Wed, Jun 17, 2026 at 07:01:32AM +0000, Kangfenglong wrote:
> Proposed fix:
> In nvme_map_cmb(), add an early return after the existing dev->cmbsz check:
> if (!dev->cmbsz)
>     return;
> + if (!nvme_cmb_size(dev))
> +    return;

Looks fine to me. Do you want to send a proper patch for it?