RE: [PATCH 02/15] cxl/core: Check physical address before mapping it in devm_cxl_iomap_block()

[Dan Williams]

Robert Richter wrote:
> The physical base address of a CXL range can be invalid and is then
> set to CXL_RESOURCE_NONE. Early check this case before mapping a
> memory block in devm_cxl_iomap_block().
> 
> Signed-off-by: Robert Richter <rrichter@xxxxxxx>
> ---
>  drivers/cxl/core/regs.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
> index 39a129c57d40..f216c017a474 100644
> --- a/drivers/cxl/core/regs.c
> +++ b/drivers/cxl/core/regs.c
> @@ -165,6 +165,9 @@ void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr,
>  	void __iomem *ret_val;
>  	struct resource *res;
>  
> +	if (addr == CXL_RESOURCE_NONE)
> +		return NULL;
> +
>  	res = devm_request_mem_region(dev, addr, length, dev_name(dev));
>  	if (!res) {
>  		resource_size_t end = addr + length - 1;
> -- 
> 2.30.2
> 

devm_request_mem_region() succeeds for you when this happens? More
details about the failure scenario please.