[libvirt] [PATCH] nodedev: update mdev_types caps before dumpxml

[Wu Zongyong]

In current implemention, mdev_types caps keep constant all
the time. But, it is possible that a device capable of
mdev_types sometime(for example:bind to proper driver) and
incapable of mdev_types at other times(for example: unbind
from its driver).
We should keep the info of xml dumped out consistent with
real status of the device.
---
 src/node_device/node_device_linux_sysfs.c | 42 +++++++++++++++++++++++++++++++
 src/node_device/node_device_udev.c        | 11 ++++++--
 src/node_device/node_device_udev.h        |  8 ++++++
 3 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/src/node_device/node_device_linux_sysfs.c b/src/node_device/node_device_linux_sysfs.c
index 6f438e5..2dc01bf 100644
--- a/src/node_device/node_device_linux_sysfs.c
+++ b/src/node_device/node_device_linux_sysfs.c
@@ -29,6 +29,7 @@
 #include "dirname.h"
 #include "node_device_driver.h"
 #include "node_device_hal.h"
+#include "node_device_udev.h"
 #include "node_device_linux_sysfs.h"
 #include "virerror.h"
 #include "viralloc.h"
@@ -175,6 +176,45 @@ nodeDeviceSysfsGetPCIIOMMUGroupCaps(virNodeDevCapPCIDevPtr pci_dev)
     return ret;
 }
 
+static int
+nodeDeviceSysfsGetPCIMdevTypesCaps(const char *sysfsPath,
+                                   virNodeDevCapPCIDevPtr pci_dev)
+{
+    size_t i;
+    int ret = -1;
+    struct udev *udev = NULL;
+    struct udev_device *device = NULL;
+
+    /* this could be a refresh, so clear out the old data */
+    for (i = 0; i < pci_dev->nmdev_types; i++)
+       VIR_FREE(pci_dev->mdev_types[i]);
+    VIR_FREE(pci_dev->mdev_types);
+    pci_dev->nmdev_types = 0;
+
+    udev = udev_new();
+    if (!udev) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("failed to create udev context"));
+        goto cleanup;
+    }
+    device = udev_device_new_from_syspath(udev, sysfsPath);
+    if (!device) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("failed to create udev device from path %s"),
+                       sysfsPath);
+        goto cleanup;
+    }
+
+    if (udevPCIGetMdevTypesCap(device, pci_dev) < 0)
+        goto cleanup;
+
+    ret = 0;
+ cleanup:
+    udev_device_unref(device);
+    udev_unref(udev);
+    return ret;
+}
+
 
 /* nodeDeviceSysfsGetPCIRelatedCaps() get info that is stored in sysfs
  * about devices related to this device, i.e. things that can change
@@ -190,6 +230,8 @@ nodeDeviceSysfsGetPCIRelatedDevCaps(const char *sysfsPath,
         return -1;
     if (nodeDeviceSysfsGetPCIIOMMUGroupCaps(pci_dev) < 0)
         return -1;
+    if (nodeDeviceSysfsGetPCIMdevTypesCaps(sysfsPath, pci_dev) < 0)
+        return -1;
     return 0;
 }
 
diff --git a/src/node_device/node_device_udev.c b/src/node_device/node_device_udev.c
index 1e1b717..256bb66 100644
--- a/src/node_device/node_device_udev.c
+++ b/src/node_device/node_device_udev.c
@@ -432,7 +432,7 @@ udevFillMdevType(struct udev_device *device,
 }
 
 
-static int
+int
 udevPCIGetMdevTypesCap(struct udev_device *device,
                        virNodeDevCapPCIDevPtr pcidata)
 {
@@ -599,8 +599,15 @@ udevProcessPCI(struct udev_device *device,
 
     /* check whether the device is mediated devices framework capable, if so,
      * process it
+     *
+     * UDEV doesn't report attributes under subdirectories by default but is
+     * able to query them if the path to the attribute is relative to the
+     * device's base path, e.g. /sys/devices/../0000:00:01.0/ is the device's
+     * base path as udev reports it, but we're interested in attributes under
+     * /sys/devices/../0000:00:01.0/mdev_supported_types/<type>/. So, we need to
+     * scan the subdirectories ourselves.
      */
-    if (udevPCIGetMdevTypesCap(device, pci_dev) < 0)
+    if (udevPCIGetMdevTypesCap(udev_device_get_syspath(device), pci_dev) < 0)
         goto cleanup;
 
     ret = 0;
diff --git a/src/node_device/node_device_udev.h b/src/node_device/node_device_udev.h
index f15e520..9f78289 100644
--- a/src/node_device/node_device_udev.h
+++ b/src/node_device/node_device_udev.h
@@ -19,6 +19,8 @@
  *
  * Author: Dave Allan <dallan at redhat.com>
  */
+#ifndef __VIR_NODE_DEVICE_UDEV_H__
+#define __VIR_NODE_DEVICE_UDEV_H__
 
 #include <libudev.h>
 #include <stdint.h>
@@ -26,3 +28,9 @@
 #define SYSFS_DATA_SIZE 4096
 #define DMI_DEVPATH "/sys/devices/virtual/dmi/id"
 #define DMI_DEVPATH_FALLBACK "/sys/class/dmi/id"
+
+int
+udevPCIGetMdevTypesCap(struct udev_device *device, virNodeDevCapPCIDevPtr pcidata);
+
+
+#endif /* __VIR_NODE_DEVICE_UDEV_H__ */
-- 
1.9.1