Re: [PATCH 06/11] PCI: rcar-gen4: Add Root Port reset support

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] cleanup: mixed goto and guard() in rcar_gen4_pcie functions
--

commit 85df5e9dd7b13dd7810d0fe2da4e91a4ae75ac30
Author: Koichiro Den <den@valinux.co.jp>
Subject: PCI: rcar-gen4: Add Root Port reset support

This commit adds Root Port reset support for the R-Car Gen4 controllers. It
implements the host bridge reset_root_port() callback, serializes the reset
with a mutex, and handles masking/unmasking APP interrupt enables during the
reset.

> diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> index 8a85f5f45cda9..5b983ef6dc47d 100644
> --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
[ ... ]
> @@ -394,6 +427,7 @@ static int rcar_gen4_pcie_host_msi_init(struct dw_pcie_rp *pp)
>  	writel(0, rcar->base + AXIINTCCONT);
>  
>  	/* Deconfigure MSI interrupt signal */
> +	guard(raw_spinlock_irqsave)(&rcar->app_lock);
>  	val = readl(rcar->base + PCIEINTSTS0EN);
>  	val &= ~MSI_CTRL_INT;
>  	writel(val, rcar->base + PCIEINTSTS0EN);

[Severity: Low]
Does this code mix scope-based cleanup with goto-based error handling?

The function rcar_gen4_pcie_host_msi_init() relies on a goto err label for
its error path. Introducing a guard() here violates the cleanup subsystem
guidelines which advise against mixing goto paradigms and scope-based cleanup
in the same function.

[ ... ]
> @@ -484,14 +518,77 @@ static int rcar_gen4_pcie_host_hw_init(struct dw_pcie_rp *pp)
[ ... ]
> +static int rcar_gen4_pcie_reset_root_port(struct pci_host_bridge *bridge,
> +					  struct pci_dev *pdev)
> +{
> +	struct rcar_gen4_pcie *rcar = dev_get_drvdata(bridge->dev.parent);
> +	struct dw_pcie *dw = &rcar->dw;
> +	struct dw_pcie_rp *pp = &dw->pp;
> +	struct device *dev = dw->dev;
> +	int ret;
> +
> +	guard(mutex)(&rcar->reset_lock);
> +
> +	rcar_gen4_pcie_quiesce_irqs(rcar);
> +
> +	dw_pcie_stop_link(dw);
> +
> +	ret = rcar_gen4_pcie_host_hw_init(pp);
> +	if (ret) {
> +		dev_err(dev, "Host init failed: %d\n", ret);
> +		goto out;
> +	}

[Severity: Low]
Is it safe to combine a guard() declaration with goto out error handling in
rcar_gen4_pcie_reset_root_port()?

The cleanup subsystem guidelines explicitly forbid mixing goto-based error
handling and guard() declarations in the same function, as it creates code
prone to double-free or resource leak bugs during future modifications.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260918032038.2216471-1-den@valinux.co.jp?part=6