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-rw-r--r--mm/backing-dev.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 5a37e205571..67a33a5a1a9 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -604,15 +604,36 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi)
/*
* Finally, kill the kernel threads. We don't need to be RCU
- * safe anymore, since the bdi is gone from visibility.
+ * safe anymore, since the bdi is gone from visibility. Force
+ * unfreeze of the thread before calling kthread_stop(), otherwise
+ * it would never exet if it is currently stuck in the refrigerator.
*/
- list_for_each_entry(wb, &bdi->wb_list, list)
+ list_for_each_entry(wb, &bdi->wb_list, list) {
+ wb->task->flags &= ~PF_FROZEN;
kthread_stop(wb->task);
+ }
+}
+
+/*
+ * This bdi is going away now, make sure that no super_blocks point to it
+ */
+static void bdi_prune_sb(struct backing_dev_info *bdi)
+{
+ struct super_block *sb;
+
+ spin_lock(&sb_lock);
+ list_for_each_entry(sb, &super_blocks, s_list) {
+ if (sb->s_bdi == bdi)
+ sb->s_bdi = NULL;
+ }
+ spin_unlock(&sb_lock);
}
void bdi_unregister(struct backing_dev_info *bdi)
{
if (bdi->dev) {
+ bdi_prune_sb(bdi);
+
if (!bdi_cap_flush_forker(bdi))
bdi_wb_shutdown(bdi);
bdi_debug_unregister(bdi);