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

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Date:   Mon, 21 Sep 2020 22:16:24 +0100
From:   Alex Dewar <alex.dewar90@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Alex Dewar <alex.dewar90@...il.com>,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        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: [PATCH v2] PCI: brcmstb: Add missing if statement and error path

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(-)

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