From 0e93680ba1b530abf58fe5da969c335a3c032eb8 Mon Sep 17 00:00:00 2001
From: Steven Rostedt <srostedt@redhat.com>
Date: Thu, 17 Mar 2011 15:21:06 -0400
Subject: [PATCH] --- yaml --- r: 242507 b: refs/heads/master c:
 2092e6be82ec71ecbf5a8ceeef004bbcbdb78812 h: refs/heads/master i:   242505:
 01a1c63580844a78b03858cf5a94c162ef21973a   242503:
 102a54db918eb3c46ef8eaae6c03a8d36f6d9733 v: v3

---
 [refs]                          |  2 +-
 trunk/include/asm-generic/bug.h | 28 +++++++++++++++++++++++++++-
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 712cc3311242..4652f19413c4 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 71f9e59800e5ad4e6b683348424c9fe54306cd43
+refs/heads/master: 2092e6be82ec71ecbf5a8ceeef004bbcbdb78812
diff --git a/trunk/include/asm-generic/bug.h b/trunk/include/asm-generic/bug.h
index c2c9ba032d46..f2d2faf4d9ae 100644
--- a/trunk/include/asm-generic/bug.h
+++ b/trunk/include/asm-generic/bug.h
@@ -165,10 +165,36 @@ extern void warn_slowpath_null(const char *file, const int line);
 #define WARN_ON_RATELIMIT(condition, state)			\
 		WARN_ON((condition) && __ratelimit(state))
 
+/*
+ * WARN_ON_SMP() is for cases that the warning is either
+ * meaningless for !SMP or may even cause failures.
+ * This is usually used for cases that we have
+ * WARN_ON(!spin_is_locked(&lock)) checks, as spin_is_locked()
+ * returns 0 for uniprocessor settings.
+ * It can also be used with values that are only defined
+ * on SMP:
+ *
+ * struct foo {
+ *  [...]
+ * #ifdef CONFIG_SMP
+ *	int bar;
+ * #endif
+ * };
+ *
+ * void func(struct foo *zoot)
+ * {
+ *	WARN_ON_SMP(!zoot->bar);
+ *
+ * For CONFIG_SMP, WARN_ON_SMP() should act the same as WARN_ON(),
+ * and should be a nop and return false for uniprocessor.
+ *
+ * if (WARN_ON_SMP(x)) returns true only when CONFIG_SMP is set
+ * and x is true.
+ */
 #ifdef CONFIG_SMP
 # define WARN_ON_SMP(x)			WARN_ON(x)
 #else
-# define WARN_ON_SMP(x)			do { } while (0)
+# define WARN_ON_SMP(x)			({0;})
 #endif
 
 #endif