linux-kernel - [PATCH] pci: controller: pci-ftpci100: Release the clock resources

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Message-Id: <20230422074254.14473-1-yejunyan@hust.edu.cn>
Date:   Sat, 22 Apr 2023 15:42:52 +0800
From:   Junyan Ye <yejunyan@...t.edu.cn>
To:     Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Wei Yongjun <weiyongjun1@...wei.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Andrew Murray <amurray@...goodpenguin.co.uk>
Cc:     hust-os-kernel-patches@...glegroups.com,
        Junyan Ye <yejunyan@...t.edu.cn>,
        Dongliang Mu <dzm91@...t.edu.cn>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] pci: controller: pci-ftpci100: Release the clock resources

Smatch reported:
1. drivers/pci/controller/pci-ftpci100.c:526 faraday_pci_probe()
warn: 'clk' from clk_prepare_enable() not released on lines:
442,451,462,478,512,517.
2. drivers/pci/controller/pci-ftpci100.c:526 faraday_pci_probe()
warn: 'p->bus_clk' from clk_prepare_enable() not released on lines:
451,462,478,512,517.

The clock resource is obtained by the devm_clk_get function. The
clk_prepare_enable function then makes the clock resource ready for use,
notifying the system that the clock resource should be run. After that,
the clock resource should be released when it is no longer needed. This
includes notifying the system that the clock resource is no longer needed
and revoking the prepared clock. The corresponding function is
clk_disable_unprepare. However, while doing some error handling in the
faraday_pci_probe function, the clk_disable_unprepare function is not
called to release the clk and p->bus_clk resources.

Fix the warning by adding the clk_disable_unprepare function before
returning the error message.

Fixes: b3c433efb8a3 ("PCI: faraday: Fix wrong pointer passed to PTR_ERR()")
Fixes: 2eeb02b28579 ("PCI: faraday: Add clock handling")
Fixes: 783a862563f7 ("PCI: faraday: Use pci_parse_request_of_pci_ranges()")
Fixes: d3c68e0a7e34 ("PCI: faraday: Add Faraday Technology FTPCI100 PCI Host Bridge driver")
Fixes: f1e8bd21e39e ("PCI: faraday: Convert IRQ masking to raw PCI config accessors")
Signed-off-by: Junyan Ye <yejunyan@...t.edu.cn>
Reviewed-by: Dongliang Mu <dzm91@...t.edu.cn>
---
This issue is found by static analyzer.

 drivers/pci/controller/pci-ftpci100.c | 31 +++++++++++++++++++--------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/controller/pci-ftpci100.c b/drivers/pci/controller/pci-ftpci100.c
index ecd3009df586..ca3ba377b3dd 100644
--- a/drivers/pci/controller/pci-ftpci100.c
+++ b/drivers/pci/controller/pci-ftpci100.c
@@ -438,17 +438,21 @@ static int faraday_pci_probe(struct platform_device *pdev)
 		return ret;
 	}
 	p->bus_clk = devm_clk_get(dev, "PCICLK");
-	if (IS_ERR(p->bus_clk))
-		return PTR_ERR(p->bus_clk);
+	if (IS_ERR(p->bus_clk)) {
+		ret = PTR_ERR(p->bus_clk);
+		goto err_release_clk;
+	}
 	ret = clk_prepare_enable(p->bus_clk);
 	if (ret) {
 		dev_err(dev, "could not prepare PCICLK\n");
-		return ret;
+		goto err_release_clk;
 	}
 
 	p->base = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(p->base))
-		return PTR_ERR(p->base);
+	if (IS_ERR(p->base)) {
+		ret = PTR_ERR(p->base);
+		goto err_release_p_bus_clk;
+	}
 
 	win = resource_list_first_type(&host->windows, IORESOURCE_IO);
 	if (win) {
@@ -459,7 +463,8 @@ static int faraday_pci_probe(struct platform_device *pdev)
 			writel(val, p->base + FTPCI_IOSIZE);
 		} else {
 			dev_err(dev, "illegal IO mem size\n");
-			return -EINVAL;
+			ret = -EINVAL;
+			goto err_release_p_bus_clk;
 		}
 	}
 
@@ -475,7 +480,7 @@ static int faraday_pci_probe(struct platform_device *pdev)
 		ret = faraday_pci_setup_cascaded_irq(p);
 		if (ret) {
 			dev_err(dev, "failed to setup cascaded IRQ\n");
-			return ret;
+			goto err_release_p_bus_clk;
 		}
 	}
 
@@ -509,12 +514,12 @@ static int faraday_pci_probe(struct platform_device *pdev)
 
 	ret = faraday_pci_parse_map_dma_ranges(p);
 	if (ret)
-		return ret;
+		goto err_release_p_bus_clk;
 
 	ret = pci_scan_root_bus_bridge(host);
 	if (ret) {
 		dev_err(dev, "failed to scan host: %d\n", ret);
-		return ret;
+		goto err_release_p_bus_clk;
 	}
 	p->bus = host->bus;
 	p->bus->max_bus_speed = max_bus_speed;
@@ -524,6 +529,14 @@ static int faraday_pci_probe(struct platform_device *pdev)
 	pci_bus_add_devices(p->bus);
 
 	return 0;
+
+err_release_p_bus_clk:
+	clk_disable_unprepare(p->bus_clk);
+
+err_release_clk:
+	clk_disable_unprepare(clk);
+
+	return ret;
 }
 
 /*
-- 
2.25.1