[PATCH] Let WARN_ON/WARN_ON_ONCE return the condition

Letting WARN_ON/WARN_ON_ONCE return the condition means that you could do

if (WARN_ON(blah)) {
	handle_impossible_case
}

Rather than

if (unlikely(blah)) {
	WARN_ON(1)
	handle_impossible_case
}

I checked all the newly added WARN_ON_ONCE users and none of them test the
return status so we can still change it.

[akpm@osdl.org: warning fix]
[akpm@osdl.org: build fix]
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 5 deletions

diff --git a/include/asm-powerpc/bug.h b/include/asm-powerpc/bug.h
index f44b529e3298..978b2c7e84ea 100644
--- a/include/asm-powerpc/bug.h
+++ b/include/asm-powerpc/bug.h
@@ -70,9 +70,10 @@ struct bug_entry *find_bug(unsigned long bugaddr);
                     "i" (__FILE__), "i" (__FUNCTION__));        \
 } while (0)
 
-#define WARN_ON(x) do {                                         \
-        if (__builtin_constant_p(x)) {                          \
-                if (x)                                          \
+#define WARN_ON(x) ({                                           \
+        typeof(x) __ret_warn_on = (x);                          \
+        if (__builtin_constant_p(__ret_warn_on)) {              \
+                if (__ret_warn_on)                              \
                         __WARN();                               \
         } else {                                                \
                 __asm__ __volatile__(                           \
@@ -80,11 +81,12 @@ struct bug_entry *find_bug(unsigned long bugaddr);
                 ".section __bug_table,\"a\"\n"                  \
                 "\t"PPC_LONG"   1b,%1,%2,%3\n"                  \
                 ".previous"                                     \
-                : : "r" ((long)(x)),                            \
+                : : "r" (__ret_warn_on),                        \
                     "i" (__LINE__ + BUG_WARNING_TRAP),          \
                     "i" (__FILE__), "i" (__FUNCTION__));        \
         }                                                       \
-} while (0)
+        unlikely(__ret_warn_on);                                \
+})
 
 #define HAVE_ARCH_BUG
 #define HAVE_ARCH_BUG_ON