Diffstat (limited to 'Documentation/sparse.txt')
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/sparse.txt b/Documentation/sparse.txt
index 4909d411635..eceab1308a8 100644
@@ -49,6 +49,24 @@ be generated without __CHECK_ENDIAN__.
__bitwise - noisy stuff; in particular, __le*/__be* are that. We really
don't want to drown in noise unless we'd explicitly asked for it.
+Using sparse for lock checking
+The following macros are undefined for gcc and defined during a sparse
+run to use the "context" tracking feature of sparse, applied to
+locking. These annotations tell sparse when a lock is held, with
+regard to the annotated function's entry and exit.
+__must_hold - The specified lock is held on function entry and exit.
+__acquires - The specified lock is held on function exit, but not entry.
+__releases - The specified lock is held on function entry, but not exit.
+If the function enters and exits without the lock held, acquiring and
+releasing the lock inside the function in a balanced way, no
+annotation is needed. The tree annotations above are for cases where
+sparse would otherwise report a context imbalance.