[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>

2 files changed, 23 insertions, 21 deletions

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 8ceab7bcd8b4..a5250895155e 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -16,12 +16,15 @@
 #endif
 
 #ifndef HAVE_ARCH_WARN_ON
-#define WARN_ON(condition) do { \
-        if (unlikely((condition)!=0)) { \
-                printk("BUG: warning at %s:%d/%s()\n", __FILE__, __LINE__, __FUNCTION__); \
-                dump_stack(); \
-        } \
-} while (0)
+#define WARN_ON(condition) ({                                           \
+        typeof(condition) __ret_warn_on = (condition);                  \
+        if (unlikely(__ret_warn_on)) {                                  \
+                printk("BUG: warning at %s:%d/%s()\n", __FILE__,        \
+                        __LINE__, __FUNCTION__);                        \
+                dump_stack();                                           \
+        }                                                               \
+        unlikely(__ret_warn_on);                                        \
+})
 #endif
 
 #else /* !CONFIG_BUG */
@@ -34,21 +37,18 @@
 #endif
 
 #ifndef HAVE_ARCH_WARN_ON
-#define WARN_ON(condition) do { if (condition) ; } while(0)
+#define WARN_ON(condition) unlikely((condition))
 #endif
 #endif
 
-#define WARN_ON_ONCE(condition)                         \
-({                                                      \
+#define WARN_ON_ONCE(condition) ({                      \
         static int __warn_once = 1;                     \
-        int __ret = 0;                                  \
+        typeof(condition) __ret_warn_once = (condition);\
                                                         \
-        if (unlikely((condition) && __warn_once)) {     \
-                __warn_once = 0;                        \
-                WARN_ON(1);                             \
-                __ret = 1;                              \
-        }                                               \
-        __ret;                                          \
+        if (likely(__warn_once))                        \
+                if (WARN_ON(__ret_warn_once))           \
+                        __warn_once = 0;                \
+        unlikely(__ret_warn_once);                      \
 })
 
 #ifdef CONFIG_SMP
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