V4L/DVB: pvrusb2: Fix USB parent device reference count

pvrusb2: Correctly reference count pointer to parent USB device when linked
from sysfs interface.  This is technically a pretty nasty problem,
however as far as I know nobody had been getting burned by it (yet).

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/media/video/pvrusb2/pvrusb2-sysfs.c b/drivers/media/video/pvrusb2/pvrusb2-sysfs.c
index 71f50565f637..bf478510a3b1 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-sysfs.c
+++ b/drivers/media/video/pvrusb2/pvrusb2-sysfs.c
@@ -511,6 +511,7 @@ static void pvr2_sysfs_release(struct device *class_dev)
 
 static void class_dev_destroy(struct pvr2_sysfs *sfp)
 {
+        struct device *dev;
         if (!sfp->class_dev) return;
 #ifdef CONFIG_VIDEO_PVRUSB2_DEBUGIFC
         pvr2_sysfs_tear_down_debugifc(sfp);
@@ -542,6 +543,9 @@ static void class_dev_destroy(struct pvr2_sysfs *sfp)
         }
         pvr2_sysfs_trace("Destroying class_dev id=%p",sfp->class_dev);
         dev_set_drvdata(sfp->class_dev, NULL);
+        dev = sfp->class_dev->parent;
+        sfp->class_dev->parent = NULL;
+        put_device(dev);
         device_unregister(sfp->class_dev);
         sfp->class_dev = NULL;
 }
@@ -631,10 +635,11 @@ static void class_dev_create(struct pvr2_sysfs *sfp,
         pvr2_sysfs_trace("Creating class_dev id=%p",class_dev);
 
         class_dev->class = &class_ptr->class;
+
         dev_set_name(class_dev, "%s",
                      pvr2_hdw_get_device_identifier(sfp->channel.hdw));
 
-        class_dev->parent = &usb_dev->dev;
+        class_dev->parent = get_device(&usb_dev->dev);
 
         sfp->class_dev = class_dev;
         dev_set_drvdata(class_dev, sfp);
@@ -775,7 +780,8 @@ struct pvr2_sysfs_class *pvr2_sysfs_class_create(void)
         struct pvr2_sysfs_class *clp;
         clp = kzalloc(sizeof(*clp),GFP_KERNEL);
         if (!clp) return clp;
-        pvr2_sysfs_trace("Creating pvr2_sysfs_class id=%p",clp);
+        pvr2_sysfs_trace("Creating and registering pvr2_sysfs_class id=%p",
+                         clp);
         clp->class.name = "pvrusb2";
         clp->class.class_release = pvr2_sysfs_class_release;
         clp->class.dev_release = pvr2_sysfs_release;
@@ -791,6 +797,7 @@ struct pvr2_sysfs_class *pvr2_sysfs_class_create(void)
 
 void pvr2_sysfs_class_destroy(struct pvr2_sysfs_class *clp)
 {
+        pvr2_sysfs_trace("Unregistering pvr2_sysfs_class id=%p", clp);
         class_unregister(&clp->class);
 }