Compilation error on 2.5.8

I get the following error when I try to compile 2.5.8 init/main.o: In function `start_kernel':
init/main.o(.text.init+0x5e2): undefined reference to `setup_per_cpu_areas'

Looking at the code it looks like someone got confused ;) around the ifdefs.I'm under the assumption that setup_per_cpu_areas() does nothing on a uniprocessor. The patch compile fine on my PC.

Quoted 9 lines · Bongani

I get the following error when I try to compile 2.5.8 init/main.o: In function `start_kernel':
init/main.o(.text.init+0x5e2): undefined reference to `setup_per_cpu_areas'

Looking at the code it looks like someone got confused ;) around the ifdefs.I'm under the assumption that setup_per_cpu_areas() does nothing on a uniprocessor. The patch compile fine on my PC.

A better approach would probably be to define setup_per_cpu_areas to nothing when CONFIG_SMP is not set so as not to have #ifdefs in the code itself ... for example,

diff -urN linux-2.5.8/init/main.c linux/init/main.c

Review

Quoted 8 lines · Bongani

Does this also look cleaner ?

(quoted diff) +3 -3

-static inline void setup_per_cpu_areas(void)
-{
-}
+
+#define setup_per_cpu_areas()  do { } while(0)
+

Personally yes, but others would disagree.

In fact, if we use a define setup_per_cpu_areas can not be used outside of this compilation unit. Right now this looks to be the case, but if something other than init/main.c wanted to use setup_per_cpu_areas we would need to make the code an actual function or put the define in a header file.

Since either case should optimize away, maybe we should make it a static inline in both cases, since that is the authors original preference ...

Robert Love

Ok, so this patch should be fine then

main.c_new Tue Apr 16 06:55:17 2002 renamed from main.c Tue Apr 16 06:52:20 2002 +4 -0

@@ -272,6 +272,10 @@
 #define smp_init()     do { } while (0)
 #endif
 
+static inline void setup_per_cpu_areas(void)
+{
+}
+
 #else
 
 #ifdef __GENERIC_PER_CPU

@@ -297,9 +301,11 @@
        }