qemu: Fix memory (and FD) leak on PCI device detach

Unmanaged PCI devices were only leaked if pciDeviceListAdd failed but
managed devices were always leaked. And leaking PCI device is likely to
leave PCI config file descriptor open. This patch fixes
qemuReattachPciDevice to either free the PCI device or add it to the
inactivePciHostdevs list.

src/qemu/qemu_hostdev.c

@@ -546,10 +546,8 @@ int qemuPrepareHostdevPCIDevices(virQEMUDriverPtr driver,
     }
 
     /* Loop 9: Now steal all the devices from pcidevs */
-    while (pciDeviceListCount(pcidevs) > 0) {
-        pciDevice *dev = pciDeviceListGet(pcidevs, 0);
-        pciDeviceListSteal(pcidevs, dev);
-    }
+    while (pciDeviceListCount(pcidevs) > 0)
+        pciDeviceListStealIndex(pcidevs, 0);
 
     ret = 0;
     goto cleanup;
@@ -818,7 +816,8 @@ void qemuReattachPciDevice(pciDevice *dev, virQEMUDriverPtr driver)
      * successfully, it must have been inactive.
      */
     if (!pciDeviceGetManaged(dev)) {
-        pciDeviceListAdd(driver->inactivePciHostdevs, dev);
+        if (pciDeviceListAdd(driver->inactivePciHostdevs, dev) < 0)
+            pciFreeDevice(dev);
         return;
     }
 
@@ -835,6 +834,7 @@ void qemuReattachPciDevice(pciDevice *dev, virQEMUDriverPtr driver)
                   err ? err->message : _("unknown error"));
         virResetError(err);
     }
+    pciFreeDevice(dev);
 }
 
 
@@ -905,8 +905,8 @@ void qemuDomainReAttachHostdevDevices(virQEMUDriverPtr driver,
         }
     }
 
-    for (i = 0; i < pciDeviceListCount(pcidevs); i++) {
-        pciDevice *dev = pciDeviceListGet(pcidevs, i);
+    while (pciDeviceListCount(pcidevs) > 0) {
+        pciDevice *dev = pciDeviceListStealIndex(pcidevs, 0);
         qemuReattachPciDevice(dev, driver);
     }