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

[Wentao Liang]

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