[MODULES]: Don't allow statically declared exports

Add an extern declaration for exported symbols to make the compiler warn
on symbols declared statically.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/module.h b/include/linux/module.h
index 70bd843c71c..d9569151c18 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -183,6 +183,7 @@ void *__symbol_get_gpl(const char *symbol);
 
 /* For every exported symbol, place a struct in the __ksymtab section */
 #define __EXPORT_SYMBOL(sym, sec)                               \
+        extern typeof(sym) sym;                                 \
         __CRC_SYMBOL(sym, sec)                                  \
         static const char __kstrtab_##sym[]                     \
         __attribute__((section("__ksymtab_strings")))           \