linux-kernel - Re: [PATCH v2] PCI: brcmstb: Add missing if statement and error path

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Message-ID: <20200923082005.GA31075@e121166-lin.cambridge.arm.com>
Date:   Wed, 23 Sep 2020 09:20:05 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Alex Dewar <alex.dewar90@...il.com>
Cc:     Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        bcm-kernel-feedback-list@...adcom.com,
        Jim Quinlan <jquinlan@...adcom.com>,
        linux-rpi-kernel@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] PCI: brcmstb: Add missing if statement and error path

On Mon, Sep 21, 2020 at 10:16:24PM +0100, Alex Dewar wrote:
> brcm_pcie_resume() contains a return statement that was presumably
> intended to have an "if (ret)" in front of it, otherwise the function
> returns prematurely. Fix this.
> 
> Additionally, redisable the clock on the error path.
> 
> I don't know if this code was tested or not, but I assume that this bug
> means that this driver will not resume properly.
> 
> Fixes: ad3d29c77e1e ("PCI: brcmstb: Add control of rescal reset")
> Addresses-Coverity: CID 1497099: Control flow issues (UNREACHABLE)
> Signed-off-by: Alex Dewar <alex.dewar90@...il.com>
> ---
> Hi Jim,
> 
> Here's a new version of the patch.
> 
> I added the missing clk_disable_unprepare() and assumed that it would
> also be required in the case that the call to brcm_pcie_setup() fails.
> 
> I didn't follow the suggestion of adding extra braces to the
> if-statement as the kernel style is not to add unnecessary braces in
> this case: https://www.kernel.org/doc/html/latest/process/coding-style.html?highlight=style#placing-braces-and-spaces
> 
> Best,
> Alex
> 
>  drivers/pci/controller/pcie-brcmstb.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)

Squashed in the original patch, pushed out in my pci/brcmstb branch,
I will drop Colin's patch following this discussion. If there is
any issue please shout, thanks.

Lorenzo

> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index 7a3ff4632e7c..8bae3a4f8e49 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -1154,7 +1154,8 @@ static int brcm_pcie_resume(struct device *dev)
>  	clk_prepare_enable(pcie->clk);
>  
>  	ret = brcm_phy_start(pcie);
> -		return ret;
> +	if (ret)
> +		goto err;
>  
>  	/* Take bridge out of reset so we can access the SERDES reg */
>  	pcie->bridge_sw_init_set(pcie, 0);
> @@ -1169,12 +1170,16 @@ static int brcm_pcie_resume(struct device *dev)
>  
>  	ret = brcm_pcie_setup(pcie);
>  	if (ret)
> -		return ret;
> +		goto err;
>  
>  	if (pcie->msi)
>  		brcm_msi_set_regs(pcie->msi);
>  
>  	return 0;
> +
> +err:
> +	clk_disable_unprepare(pcie->clk);
> +	return ret;
>  }
>  
>  static void __brcm_pcie_remove(struct brcm_pcie *pcie)
> -- 
> 2.28.0
>