Merge git://oss.sgi.com:8090/xfs/linux-2.6

* git://oss.sgi.com:8090/xfs/linux-2.6: (45 commits)
  [XFS] Fix use after free in xfs_log_done().
  [XFS] Make xfs_bmap_*_count_leaves void.
  [XFS] Use KM_NOFS for debug trace buffers
  [XFS] use KM_MAYFAIL in xfs_mountfs
  [XFS] refactor xfs_mount_free
  [XFS] don't call xfs_freesb from xfs_unmountfs
  [XFS] xfs_unmountfs should return void
  [XFS] cleanup xfs_mountfs
  [XFS] move root inode IRELE into xfs_unmountfs
  [XFS] stop using file_update_time
  [XFS] optimize xfs_ichgtime
  [XFS] update timestamp in xfs_ialloc manually
  [XFS] remove the sema_t from XFS.
  [XFS] replace dquot flush semaphore with a completion
  [XFS] replace inode flush semaphore with a completion
  [XFS] extend completions to provide XFS object flush requirements
  [XFS] replace the XFS buf iodone semaphore with a completion
  [XFS] clean up stale references to semaphores
  [XFS] use get_unaligned_* helpers
  [XFS] Fix compile failure in xfs_buf_trace()
  ...

1 files changed, 45 insertions, 0 deletions

diff --git a/include/linux/completion.h b/include/linux/completion.h
index d2961b66d53d..57faa60de9bd 100644
--- a/include/linux/completion.h
+++ b/include/linux/completion.h
@@ -55,4 +55,49 @@ extern void complete_all(struct completion *);
 
 #define INIT_COMPLETION(x)      ((x).done = 0)
 
+
+/**
+ *      try_wait_for_completion - try to decrement a completion without blocking
+ *      @x:     completion structure
+ *
+ *      Returns: 0 if a decrement cannot be done without blocking
+ *               1 if a decrement succeeded.
+ *
+ *      If a completion is being used as a counting completion,
+ *      attempt to decrement the counter without blocking. This
+ *      enables us to avoid waiting if the resource the completion
+ *      is protecting is not available.
+ */
+static inline bool try_wait_for_completion(struct completion *x)
+{
+        int ret = 1;
+
+        spin_lock_irq(&x->wait.lock);
+        if (!x->done)
+                ret = 0;
+        else
+                x->done--;
+        spin_unlock_irq(&x->wait.lock);
+        return ret;
+}
+
+/**
+ *      completion_done - Test to see if a completion has any waiters
+ *      @x:     completion structure
+ *
+ *      Returns: 0 if there are waiters (wait_for_completion() in progress)
+ *               1 if there are no waiters.
+ *
+ */
+static inline bool completion_done(struct completion *x)
+{
+        int ret = 1;
+
+        spin_lock_irq(&x->wait.lock);
+        if (!x->done)
+                ret = 0;
+        spin_unlock_irq(&x->wait.lock);
+        return ret;
+}
+
 #endif