[PATCH] xen/pcifront: Fix PCI device reference leak in pcifront_common_process()

[Wentao Liang <vulab@xxxxxxxxxxx>]

pcifront_common_process() gets a reference to the PCI device with
pci_get_domain_bus_and_slot() and only drops it on the early error
path.  Returning directly from the AER handler switch instead of
recording the result and falling through to the common
pci_dev_put(pcidev) leaks the reference on every successful call.

Collect the handler result in a variable and drop the reference on the
single exit path again.

Fixes: 34ab316d7287 ("xen/pcifront: Drop pcifront_common_process() tests of 
pcidev, pdrv")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
---
 drivers/pci/xen-pcifront.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
index cffc32d66032..5fdce7c41af5 100644
--- a/drivers/pci/xen-pcifront.c
+++ b/drivers/pci/xen-pcifront.c
@@ -579,6 +579,7 @@ static pci_ers_result_t pcifront_common_process(int cmd,
        int bus = pdev->sh_info->aer_op.bus;
        int devfn = pdev->sh_info->aer_op.devfn;
        int domain = pdev->sh_info->aer_op.domain;
+       pci_ers_result_t result = PCI_ERS_RESULT_NONE;
        struct pci_dev *pcidev;
 
        dev_dbg(&pdev->xdev->dev,
@@ -597,21 +598,25 @@ static pci_ers_result_t pcifront_common_process(int cmd,
                pci_dbg(pcidev, "trying to call AER service\n");
                switch (cmd) {
                case XEN_PCI_OP_aer_detected:
-                       return pdrv->err_handler->error_detected(pcidev, state);
+                       result = pdrv->err_handler->error_detected(pcidev, 
state);
+                       break;
                case XEN_PCI_OP_aer_mmio:
-                       return pdrv->err_handler->mmio_enabled(pcidev);
+                       result = pdrv->err_handler->mmio_enabled(pcidev);
+                       break;
                case XEN_PCI_OP_aer_slotreset:
-                       return pdrv->err_handler->slot_reset(pcidev);
+                       result = pdrv->err_handler->slot_reset(pcidev);
+                       break;
                case XEN_PCI_OP_aer_resume:
                        pdrv->err_handler->resume(pcidev);
-                       return PCI_ERS_RESULT_NONE;
+                       break;
                default:
                        dev_err(&pdev->xdev->dev,
                                "bad request in aer recovery operation!\n");
                }
        }
 
-       return PCI_ERS_RESULT_NONE;
+       pci_dev_put(pcidev);
+       return result;
 }
 
 
-- 
2.34.1