[PATCH v3] nvme-pci: fix CMB mapping when CMBSZ Size field is zero

[Kanchan Joshi]

On 6/22/2026 8:11 AM, kangfenglong wrote:
>   static void nvme_map_cmb(struct nvme_dev *dev)
>   {
> -	u64 size, offset;
> +	u64 size, unit_size, offset;
>   	resource_size_t bar_size;
>   	struct pci_dev *pdev = to_pci_dev(dev->dev);
>   	int bar;
> @@ -2472,9 +2475,15 @@ static void nvme_map_cmb(struct nvme_dev *dev)
>   	dev->cmbsz = readl(dev->bar + NVME_REG_CMBSZ);
>   	if (!dev->cmbsz)
>   		return;
> +	if (!nvme_cmb_size(dev))
> +		return;
>   	dev->cmbloc = readl(dev->bar + NVME_REG_CMBLOC);
>   
> -	size = nvme_cmb_size_unit(dev) * nvme_cmb_size(dev);
> +	unit_size = nvme_cmb_size_unit(dev);
> +	if (!unit_size)
> +		return;
> +	if (check_mul_overflow(unit_size, nvme_cmb_size(dev), &size))
> +		return;
>   	offset = nvme_cmb_size_unit(dev) * NVME_CMB_OFST(dev->cmbloc);

nit: now unit_size can be used in this line.

With that, LGTM.

Reviewed-by: Kanchan Joshi <joshi.k at samsung.com>