[PATCH v2 2/2] PCI: altera: Fix resource leaks on probe failure

[Mahesh Vaidya <mahesh.vaidya@altera.com>]

The chained IRQ handler is installed during probe but is only removed
from the remove path. If pci_host_probe() fails, the handler and INTx IRQ
domain remain installed even though the devm-managed host bridge storage
containing struct altera_pcie will be released, leaving the handler with
a stale data pointer.

Interrupts are also enabled before pci_host_probe() is called. If probe
fails after that point, the controller interrupt source should be disabled
before the chained handler and INTx domain are removed.

Install the chained handler only after the INTx domain has been created.
Disable controller interrupts during IRQ teardown, and tear the IRQ setup
down if pci_host_probe() fails.

Fixes: c63aed7334c2 ("PCI: altera: Use pci_host_probe() to register host")
Cc: stable@vger.kernel.org
Reviewed-by: Subhransu S. Prusty <subhransu.sekhar.prusty@altera.com>
Signed-off-by: Mahesh Vaidya <mahesh.vaidya@altera.com>
---
 drivers/pci/controller/pcie-altera.c | 35 ++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-altera.c b/drivers/pci/controller/pcie-altera.c
index 3d3519b8d88f..902ae2d81763 100644
--- a/drivers/pci/controller/pcie-altera.c
+++ b/drivers/pci/controller/pcie-altera.c
@@ -864,8 +864,23 @@ static int altera_pcie_init_irq_domain(struct altera_pcie *pcie)
 	return 0;
 }
 
+static void altera_pcie_disable_irq(struct altera_pcie *pcie)
+{
+	if (pcie->pcie_data->version == ALTERA_PCIE_V1 ||
+	    pcie->pcie_data->version == ALTERA_PCIE_V2) {
+		/* Disable all P2A interrupts */
+		cra_writel(pcie, 0, P2A_INT_ENABLE);
+	} else if (pcie->pcie_data->version == ALTERA_PCIE_V3) {
+		/* Disable port-level interrupts (CFG_AER, etc.) */
+		writel(0, pcie->hip_base +
+			  pcie->pcie_data->port_conf_offset +
+			  pcie->pcie_data->port_irq_enable_offset);
+	}
+}
+
 static void altera_pcie_irq_teardown(struct altera_pcie *pcie)
 {
+	altera_pcie_disable_irq(pcie);
 	irq_set_chained_handler_and_data(pcie->irq, NULL, NULL);
 	irq_domain_remove(pcie->irq_domain);
 }
@@ -890,7 +905,6 @@ static int altera_pcie_parse_dt(struct altera_pcie *pcie)
 	if (pcie->irq < 0)
 		return pcie->irq;
 
-	irq_set_chained_handler_and_data(pcie->irq, pcie->pcie_data->ops->rp_isr, pcie);
 	return 0;
 }
 
@@ -1019,6 +1033,14 @@ static int altera_pcie_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	/*
+	 * The chained handler uses pcie->irq_domain, so install it
+	 * only after the INTx domain has been created.
+	 */
+	irq_set_chained_handler_and_data(pcie->irq,
+					 pcie->pcie_data->ops->rp_isr,
+					 pcie);
+
 	if (pcie->pcie_data->version == ALTERA_PCIE_V1 ||
 	    pcie->pcie_data->version == ALTERA_PCIE_V2) {
 		/* clear all interrupts */
@@ -1036,7 +1058,16 @@ static int altera_pcie_probe(struct platform_device *pdev)
 	bridge->busnr = pcie->root_bus_nr;
 	bridge->ops = &altera_pcie_ops;
 
-	return pci_host_probe(bridge);
+	ret = pci_host_probe(bridge);
+	if (ret)
+		goto err_teardown_irq;
+
+	return 0;
+
+err_teardown_irq:
+	altera_pcie_irq_teardown(pcie);
+
+	return ret;
 }
 
 static void altera_pcie_remove(struct platform_device *pdev)
-- 
2.34.1