diff options
authorLinus Torvalds <torvalds@linux-foundation.org>2009-04-07 07:59:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-07 09:05:35 -0700
commitaeeae86859f4319de0a4946b44771d9926eeed54 (patch)
parent985c0cd3f75b5a546ceab002e36b4263f2f7d2c3 (diff)
Fix build errors due to CONFIG_BRANCH_TRACER=y
The code that enables branch tracing for all (non-constant) branches plays games with the preprocessor and #define's the C 'if ()' construct to do tracing. That's all fine, but it fails for some unusual but valid C code that is sometimes used in macros, notably by the intel-iommu code: if (i=drhd->iommu, drhd->ignored) .. because now the preprocessor complains about multiple arguments to the 'if' macro. So make the macro expansion of this particularly horrid trick use varargs, and handle the case of comma-expressions in if-statements. Use another macro to do it cleanly in just one place. This replaces a patch by David (and acked by Steven) that did this all inside that one already-too-horrid macro. Tested-by: Ingo Molnar <mingo@elte.hu> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 6faa7e549de4..cebfdcd3dbdd 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -114,7 +114,9 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
* "Define 'is'", Bill Clinton
* "Define 'if'", Steven Rostedt
-#define if(cond) if (__builtin_constant_p((cond)) ? !!(cond) : \
+#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
+#define __trace_if(cond) \
+ if (__builtin_constant_p((cond)) ? !!(cond) : \
({ \
int ______r; \
static struct ftrace_branch_data \

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