[PATCH net v2] ixgbe: fix pci device refcount leak

[PATCH net v2] ixgbe: fix pci device refcount leak

[Yang Yingliang]

As the comment of pci_get_domain_bus_and_slot() says, it
returns a PCI device with refcount incremented, when finish
using it, the caller must decrement the reference count by
calling pci_dev_put().

In ixgbe_get_first_secondary_devfn() and ixgbe_x550em_a_has_mii(),
pci_dev_put() is called to avoid leak.

Fixes: 8fa10ef01260 ("ixgbe: register a mdiobus")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
v1 -> v2:
  Introduce a local variable, and put pci_dev_put() after value checks.
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
index 24aa97f993ca..123dca9ce468 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
@@ -855,9 +855,11 @@ static struct pci_dev *ixgbe_get_first_secondary_devfn(unsigned int devfn)
 	rp_pdev = pci_get_domain_bus_and_slot(0, 0, devfn);
 	if (rp_pdev && rp_pdev->subordinate) {
 		bus = rp_pdev->subordinate->number;
+		pci_dev_put(rp_pdev);
 		return pci_get_domain_bus_and_slot(0, bus, 0);
 	}
 
+	pci_dev_put(rp_pdev);
 	return NULL;
 }
 
@@ -874,6 +876,7 @@ static bool ixgbe_x550em_a_has_mii(struct ixgbe_hw *hw)
 	struct ixgbe_adapter *adapter = hw->back;
 	struct pci_dev *pdev = adapter->pdev;
 	struct pci_dev *func0_pdev;
+	bool has_mii = false;
 
 	/* For the C3000 family of SoCs (x550em_a) the internal ixgbe devices
 	 * are always downstream of root ports @ 0000:00:16.0 & 0000:00:17.0
@@ -884,15 +887,16 @@ static bool ixgbe_x550em_a_has_mii(struct ixgbe_hw *hw)
 	func0_pdev = ixgbe_get_first_secondary_devfn(PCI_DEVFN(0x16, 0));
 	if (func0_pdev) {
 		if (func0_pdev == pdev)
-			return true;
-		else
-			return false;
+			has_mii = true;
+		goto out;
 	}
 	func0_pdev = ixgbe_get_first_secondary_devfn(PCI_DEVFN(0x17, 0));
 	if (func0_pdev == pdev)
-		return true;
+		has_mii = true;
 
-	return false;
+out:
+	pci_dev_put(func0_pdev);
+	return has_mii;
 }
 
 /**
-- 
2.25.1

RE: [Intel-wired-lan] [PATCH net v2] ixgbe: fix pci device refcount leak

[G, GurucharanX]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
> Yang Yingliang
> Sent: Tuesday, November 29, 2022 7:28 AM
> To: netdev@vger.kernel.org; intel-wired-lan@lists.osuosl.org
> Cc: andrew@lunn.ch; f.fainelli@gmail.com; stephend@silicom-usa.com;
> edumazet@google.com; jeffrey.t.kirsher@intel.com; kuba@kernel.org;
> pabeni@redhat.com; davem@davemloft.net
> Subject: [Intel-wired-lan] [PATCH net v2] ixgbe: fix pci device refcount leak
> 
> As the comment of pci_get_domain_bus_and_slot() says, it returns a PCI
> device with refcount incremented, when finish using it, the caller must
> decrement the reference count by calling pci_dev_put().
> 
> In ixgbe_get_first_secondary_devfn() and ixgbe_x550em_a_has_mii(),
> pci_dev_put() is called to avoid leak.
> 
> Fixes: 8fa10ef01260 ("ixgbe: register a mdiobus")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
> v1 -> v2:
>   Introduce a local variable, and put pci_dev_put() after value checks.
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 

Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)