Re: [PATCH] PCI: dwc: Reject a negative nr_irqs value in dw_pcie_edma_irq_verify()

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Fri, Dec 20, 2024 at 08:23:29AM +0100, Niklas Cassel wrote:
> Platforms that do not have (one or more) dedicated IRQs for the eDMA
> need to set nr_irqs to a non-zero value in their DWC glue driver.
> 
> Platforms that do have (one or more) dedicated IRQs do not need to
> initialize nr_irqs. DWC common code will automatically set nr_irqs.
> 
> Since a glue driver can initialize nr_irqs, dw_pcie_edma_irq_verify()
> should verify that nr_irqs, if non-zero, is a valid value. Thus, add a
> check in dw_pcie_edma_irq_verify() to reject a negative nr_irqs value.
> 

Why can't we make dw_edma_chip::nr_irqs unsigned?

- Mani

> This fixes the following build warning when compiling with W=1:
> 
> drivers/pci/controller/dwc/pcie-designware.c: In function ‘dw_pcie_edma_detect’:
> drivers/pci/controller/dwc/pcie-designware.c:989:50: warning: ‘%d’ directive output may be truncated writing between 1 and 11 bytes into a region of size 3 [-Wformat-truncation=]
>   989 |                 snprintf(name, sizeof(name), "dma%d", pci->edma.nr_irqs);
>       |                                                  ^~
> 
> Signed-off-by: Niklas Cassel <cassel@kernel.org>
> ---
>  drivers/pci/controller/dwc/pcie-designware.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> index 3c683b6119c3..d7f695d5dbc4 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.c
> +++ b/drivers/pci/controller/dwc/pcie-designware.c
> @@ -978,6 +978,8 @@ static int dw_pcie_edma_irq_verify(struct dw_pcie *pci)
>  		return 0;
>  	else if (pci->edma.nr_irqs > 1)
>  		return pci->edma.nr_irqs != ch_cnt ? -EINVAL : 0;
> +	else if (pci->edma.nr_irqs < 0)
> +		return -EINVAL;
>  
>  	ret = platform_get_irq_byname_optional(pdev, "dma");
>  	if (ret > 0) {
> -- 
> 2.47.1
> 

-- 
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