Merge branch 'stable-3.2' into pandora-3.2

[pandora-kernel.git] / drivers / pps / pps.c

diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
index 2baadd2..e83669f 100644 (file)
--- a/drivers/pps/pps.c
+++ b/drivers/pps/pps.c
@@ -247,12 +247,15 @@ static int pps_cdev_open(struct inode *inode, struct file *file)
        struct pps_device *pps = container_of(inode->i_cdev,
                                                struct pps_device, cdev);
        file->private_data = pps;
-
+       kobject_get(&pps->dev->kobj);
        return 0;
 }
 
 static int pps_cdev_release(struct inode *inode, struct file *file)
 {
+       struct pps_device *pps = container_of(inode->i_cdev,
+                                               struct pps_device, cdev);
+       kobject_put(&pps->dev->kobj);
        return 0;
 }
 
@@ -274,8 +277,10 @@ static void pps_device_destruct(struct device *dev)
 {
        struct pps_device *pps = dev_get_drvdata(dev);
 
-       /* release id here to protect others from using it while it's
-        * still in use */
+       cdev_del(&pps->cdev);
+
+       /* Now we can release the ID for re-use */
+       pr_debug("deallocating pps%d\n", pps->id);
        mutex_lock(&pps_idr_lock);
        idr_remove(&pps_idr, pps->id);
        mutex_unlock(&pps_idr_lock);
@@ -330,6 +335,7 @@ int pps_register_cdev(struct pps_device *pps)
        if (IS_ERR(pps->dev))
                goto del_cdev;
 
+       /* Override the release function with our own */
        pps->dev->release = pps_device_destruct;
 
        pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
@@ -350,10 +356,43 @@ free_idr:
 
 void pps_unregister_cdev(struct pps_device *pps)
 {
+       pr_debug("unregistering pps%d\n", pps->id);
+       pps->lookup_cookie = NULL;
        device_destroy(pps_class, pps->dev->devt);
-       cdev_del(&pps->cdev);
 }
 
+/*
+ * Look up a pps device by magic cookie.
+ * The cookie is usually a pointer to some enclosing device, but this
+ * code doesn't care; you should never be dereferencing it.
+ *
+ * This is a bit of a kludge that is currently used only by the PPS
+ * serial line discipline.  It may need to be tweaked when a second user
+ * is found.
+ *
+ * There is no function interface for setting the lookup_cookie field.
+ * It's initialized to NULL when the pps device is created, and if a
+ * client wants to use it, just fill it in afterward.
+ *
+ * The cookie is automatically set to NULL in pps_unregister_source()
+ * so that it will not be used again, even if the pps device cannot
+ * be removed from the idr due to pending references holding the minor
+ * number in use.
+ */
+struct pps_device *pps_lookup_dev(void const *cookie)
+{
+       struct pps_device *pps;
+       unsigned id;
+
+       rcu_read_lock();
+       idr_for_each_entry(&pps_idr, pps, id)
+               if (cookie == pps->lookup_cookie)
+                       break;
+       rcu_read_unlock();
+       return pps;
+}
+EXPORT_SYMBOL(pps_lookup_dev);
+
 /*
  * Module stuff
  */