include/linux/compiler-gcc.h: improve __visible documentation
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 0e3110a..22ab246 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -205,7 +205,10 @@
#if GCC_VERSION >= 40600
/*
- * Tell the optimizer that something else uses this function or variable.
+ * When used with Link Time Optimization, gcc can optimize away C functions or
+ * variables which are referenced only from assembly code. __visible tells the
+ * optimizer that something else uses this function or variable, thus preventing
+ * this.
*/
#define __visible __attribute__((externally_visible))
#endif
