[ARM] 4764/1: [AT91] AT91CAP9 core support

[linux-2.6-omap-h63xx.git] / fs / locks.c

diff --git a/fs/locks.c b/fs/locks.c
index 0127a2846819148df5b9a8722118e11ed60e253b..8b8388eca05e88bde827d97bc71193247c190e86 100644 (file)
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -696,17 +696,28 @@ EXPORT_SYMBOL(posix_test_lock);
  * Note: the above assumption may not be true when handling lock requests
  * from a broken NFS client. But broken NFS clients have a lot more to
  * worry about than proper deadlock detection anyway... --okir
+ *
+ * However, the failure of this assumption (also possible in the case of
+ * multiple tasks sharing the same open file table) also means there's no
+ * guarantee that the loop below will terminate.  As a hack, we give up
+ * after a few iterations.
  */
+
+#define MAX_DEADLK_ITERATIONS 10
+
 static int posix_locks_deadlock(struct file_lock *caller_fl,
                                struct file_lock *block_fl)
 {
        struct file_lock *fl;
+       int i = 0;
 
 next_task:
        if (posix_same_owner(caller_fl, block_fl))
                return 1;
        list_for_each_entry(fl, &blocked_list, fl_link) {
                if (posix_same_owner(fl, block_fl)) {
+                       if (i++ > MAX_DEADLK_ITERATIONS)
+                               return 0;
                        fl = fl->fl_next;
                        block_fl = fl;
                        goto next_task;