From 2092e6be82ec71ecbf5a8ceeef004bbcbdb78812 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 17 Mar 2011 15:21:06 -0400 Subject: WARN_ON_SMP(): Allow use in if() statements on UP Both WARN_ON() and WARN_ON_SMP() should be able to be used in an if statement. if (WARN_ON_SMP(foo)) { ... } Because WARN_ON_SMP() is defined as a do { } while (0) on UP, it can not be used this way. Convert it to the same form that WARN_ON() is, even when CONFIG_SMP is off. Signed-off-by: Steven Rostedt Acked-by: Thomas Gleixner Acked-by: Peter Zijlstra Acked-by: Darren Hart Cc: Lai Jiangshan Cc: Linus Torvalds Cc: Andrew Morton LKML-Reference: <20110317192208.444147791@goodmis.org> Signed-off-by: Ingo Molnar --- include/asm-generic/bug.h | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index c2c9ba0..f2d2faf 100644 --- a/include/asm-generic/bug.h +++ b/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 -- cgit v1.1