omap2+: add drm device

[pandora-kernel.git] / mm / backing-dev.c

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index a086064..2b49dd2 100644 (file)
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -318,7 +318,7 @@ static void wakeup_timer_fn(unsigned long data)
        if (bdi->wb.task) {
                trace_writeback_wake_thread(bdi);
                wake_up_process(bdi->wb.task);
-       } else {
+       } else if (bdi->dev) {
                /*
                 * When bdi tasks are inactive for long time, they are killed.
                 * In this case we have to wake-up the forker thread which
@@ -584,6 +584,8 @@ EXPORT_SYMBOL(bdi_register_dev);
  */
 static void bdi_wb_shutdown(struct backing_dev_info *bdi)
 {
+       struct task_struct *task;
+
        if (!bdi_cap_writeback_dirty(bdi))
                return;
 
@@ -604,9 +606,14 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi)
         * unfreeze of the thread before calling kthread_stop(), otherwise
         * it would never exet if it is currently stuck in the refrigerator.
         */
-       if (bdi->wb.task) {
-               thaw_process(bdi->wb.task);
-               kthread_stop(bdi->wb.task);
+       spin_lock_bh(&bdi->wb_lock);
+       task = bdi->wb.task;
+       bdi->wb.task = NULL;
+       spin_unlock_bh(&bdi->wb_lock);
+
+       if (task) {
+               thaw_process(task);
+               kthread_stop(task);
        }
 }
 
@@ -627,7 +634,9 @@ static void bdi_prune_sb(struct backing_dev_info *bdi)
 
 void bdi_unregister(struct backing_dev_info *bdi)
 {
-       if (bdi->dev) {
+       struct device *dev = bdi->dev;
+
+       if (dev) {
                bdi_set_min_ratio(bdi, 0);
                trace_writeback_bdi_unregister(bdi);
                bdi_prune_sb(bdi);
@@ -636,8 +645,12 @@ void bdi_unregister(struct backing_dev_info *bdi)
                if (!bdi_cap_flush_forker(bdi))
                        bdi_wb_shutdown(bdi);
                bdi_debug_unregister(bdi);
-               device_unregister(bdi->dev);
+
+               spin_lock_bh(&bdi->wb_lock);
                bdi->dev = NULL;
+               spin_unlock_bh(&bdi->wb_lock);
+
+               device_unregister(dev);
        }
 }
 EXPORT_SYMBOL(bdi_unregister);
@@ -724,6 +737,14 @@ void bdi_destroy(struct backing_dev_info *bdi)
 
        bdi_unregister(bdi);
 
+       /*
+        * If bdi_unregister() had already been called earlier, the
+        * wakeup_timer could still be armed because bdi_prune_sb()
+        * can race with the bdi_wakeup_thread_delayed() calls from
+        * __mark_inode_dirty().
+        */
+       del_timer_sync(&bdi->wb.wakeup_timer);
+
        for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
                percpu_counter_destroy(&bdi->bdi_stat[i]);