Document SPIN_LOCK_UNLOCKED/RW_LOCK_UNLOCKED deprecation
Apparently it's not cool anymore to use SPIN/RW_LOCK_UNLOCKED. There's
some mention of this in Documentation/spinlocks.txt, but that only talks
about dynamic initialisation.
A comment in the code mentioning the preferred usage would be good IMHO.
[akpm@linux-foundation.org: add reason for deprecation]
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/spinlock_types.h b/include/linux/spinlock_types.h
index dc5fb69..210549b 100644
--- a/include/linux/spinlock_types.h
+++ b/include/linux/spinlock_types.h
@@ -85,6 +85,12 @@
RW_DEP_MAP_INIT(lockname) }
#endif
+/*
+ * SPIN_LOCK_UNLOCKED and RW_LOCK_UNLOCKED defeat lockdep state tracking and
+ * are hence deprecated.
+ * Please use DEFINE_SPINLOCK()/DEFINE_RWLOCK() or
+ * __SPIN_LOCK_UNLOCKED()/__RW_LOCK_UNLOCKED() as appropriate.
+ */
#define SPIN_LOCK_UNLOCKED __SPIN_LOCK_UNLOCKED(old_style_spin_init)
#define RW_LOCK_UNLOCKED __RW_LOCK_UNLOCKED(old_style_rw_init)