xen-pciback: properly clean up after calling pcistub_device_find()

As the function calls pcistub_device_get() before returning non-NULL,
its callers need to take care of calling pcistub_device_put() on
(mostly, but not exclusively) error paths.

Otoh, the function already guarantees that the 'dev' member is non-NULL
upon successful return, so callers do not need to check for this a
second time.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
index 20e1c42..acec6fa 100644 (file)
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -681,14 +681,14 @@ static pci_ers_result_t xen_pcibk_slot_reset(struct pci_dev *dev)
                dev_err(&dev->dev, DRV_NAME " device is not connected or owned"
                        " by HVM, kill it\n");
                kill_domain_by_device(psdev);
-               goto release;
+               goto end;
        }
 
        if (!test_bit(_XEN_PCIB_AERHANDLER,
                (unsigned long *)&psdev->pdev->sh_info->flags)) {
                dev_err(&dev->dev,
                        "guest with no AER driver should have been killed\n");
-               goto release;
+               goto end;
        }
        result = common_process(psdev, 1, XEN_PCI_OP_aer_slotreset, result);
 
@@ -698,9 +698,9 @@ static pci_ers_result_t xen_pcibk_slot_reset(struct pci_dev *dev)
                        "No AER slot_reset service or disconnected!\n");
                kill_domain_by_device(psdev);
        }
-release:
-       pcistub_device_put(psdev);
 end:
+       if (psdev)
+               pcistub_device_put(psdev);
        up_write(&pcistub_sem);
        return result;
 
@@ -739,14 +739,14 @@ static pci_ers_result_t xen_pcibk_mmio_enabled(struct pci_dev *dev)
                dev_err(&dev->dev, DRV_NAME " device is not connected or owned"
                        " by HVM, kill it\n");
                kill_domain_by_device(psdev);
-               goto release;
+               goto end;
        }
 
        if (!test_bit(_XEN_PCIB_AERHANDLER,
                (unsigned long *)&psdev->pdev->sh_info->flags)) {
                dev_err(&dev->dev,
                        "guest with no AER driver should have been killed\n");
-               goto release;
+               goto end;
        }
        result = common_process(psdev, 1, XEN_PCI_OP_aer_mmio, result);
 
@@ -756,9 +756,9 @@ static pci_ers_result_t xen_pcibk_mmio_enabled(struct pci_dev *dev)
                        "No AER mmio_enabled service or disconnected!\n");
                kill_domain_by_device(psdev);
        }
-release:
-       pcistub_device_put(psdev);
 end:
+       if (psdev)
+               pcistub_device_put(psdev);
        up_write(&pcistub_sem);
        return result;
 }
@@ -797,7 +797,7 @@ static pci_ers_result_t xen_pcibk_error_detected(struct pci_dev *dev,
                dev_err(&dev->dev, DRV_NAME " device is not connected or owned"
                        " by HVM, kill it\n");
                kill_domain_by_device(psdev);
-               goto release;
+               goto end;
        }
 
        /*Guest owns the device yet no aer handler regiested, kill guest*/
@@ -805,7 +805,7 @@ static pci_ers_result_t xen_pcibk_error_detected(struct pci_dev *dev,
                (unsigned long *)&psdev->pdev->sh_info->flags)) {
                dev_dbg(&dev->dev, "guest may have no aer driver, kill it\n");
                kill_domain_by_device(psdev);
-               goto release;
+               goto end;
        }
        result = common_process(psdev, error, XEN_PCI_OP_aer_detected, result);
 
@@ -815,9 +815,9 @@ static pci_ers_result_t xen_pcibk_error_detected(struct pci_dev *dev,
                        "No AER error_detected service or disconnected!\n");
                kill_domain_by_device(psdev);
        }
-release:
-       pcistub_device_put(psdev);
 end:
+       if (psdev)
+               pcistub_device_put(psdev);
        up_write(&pcistub_sem);
        return result;
 }
@@ -851,7 +851,7 @@ static void xen_pcibk_error_resume(struct pci_dev *dev)
                dev_err(&dev->dev, DRV_NAME " device is not connected or owned"
                        " by HVM, kill it\n");
                kill_domain_by_device(psdev);
-               goto release;
+               goto end;
        }
 
        if (!test_bit(_XEN_PCIB_AERHANDLER,
@@ -859,13 +859,13 @@ static void xen_pcibk_error_resume(struct pci_dev *dev)
                dev_err(&dev->dev,
                        "guest with no AER driver should have been killed\n");
                kill_domain_by_device(psdev);
-               goto release;
+               goto end;
        }
        common_process(psdev, 1, XEN_PCI_OP_aer_resume,
                       PCI_ERS_RESULT_RECOVERED);
-release:
-       pcistub_device_put(psdev);
 end:
+       if (psdev)
+               pcistub_device_put(psdev);
        up_write(&pcistub_sem);
        return;
 }
@@ -1024,7 +1024,7 @@ static int pcistub_reg_add(int domain, int bus, int slot, int func, int reg,
        struct config_field *field;
 
        psdev = pcistub_device_find(domain, bus, slot, func);
-       if (!psdev || !psdev->dev) {
+       if (!psdev) {
                err = -ENODEV;
                goto out;
        }
@@ -1048,6 +1048,8 @@ static int pcistub_reg_add(int domain, int bus, int slot, int func, int reg,
        if (err)
                kfree(field);
 out:
+       if (psdev)
+               pcistub_device_put(psdev);
        return err;
 }
 
@@ -1152,10 +1154,9 @@ static ssize_t pcistub_irq_handler_switch(struct device_driver *drv,
 
        err = str_to_slot(buf, &domain, &bus, &slot, &func);
        if (err)
-               goto out;
+               return err;
 
        psdev = pcistub_device_find(domain, bus, slot, func);
-
        if (!psdev)
                goto out;
 
@@ -1171,6 +1172,8 @@ static ssize_t pcistub_irq_handler_switch(struct device_driver *drv,
        if (dev_data->isr_on)
                dev_data->ack_intr = 1;
 out:
+       if (psdev)
+               pcistub_device_put(psdev);
        if (!err)
                err = count;
        return err;
@@ -1262,10 +1265,7 @@ static ssize_t permissive_add(struct device_driver *drv, const char *buf,
                err = -ENODEV;
                goto out;
        }
-       if (!psdev->dev) {
-               err = -ENODEV;
-               goto release;
-       }
+
        dev_data = pci_get_drvdata(psdev->dev);
        /* the driver data for a device should never be null at this point */
        if (!dev_data) {