[PATCH] Add EXPORT_UNUSED_SYMBOL and EXPORT_UNUSED_SYMBOL_GPL

Temporarily add EXPORT_UNUSED_SYMBOL and EXPORT_UNUSED_SYMBOL_GPL.  These
will be used as a transition measure for symbols that aren't used in the
kernel and are on the way out.  When a module uses such a symbol, a warning
is printk'd at modprobe time.

The main reason for removing unused exports is size: eacho export takes
roughly between 100 and 150 bytes of kernel space in the binary.  This
patch gives users the option to immediately get this size gain via a config
option.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 5330911ebd30..e4fcbd12cf6e 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -23,6 +23,22 @@ config MAGIC_SYSRQ
           keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
           unless you really know what this hack does.
 
+config UNUSED_SYMBOLS
+        bool "Enable unused/obsolete exported symbols"
+        default y if X86
+        help
+          Unused but exported symbols make the kernel needlessly bigger.  For
+          that reason most of these unused exports will soon be removed.  This
+          option is provided temporarily to provide a transition period in case
+          some external kernel module needs one of these symbols anyway. If you
+          encounter such a case in your module, consider if you are actually
+          using the right API.  (rationale: since nobody in the kernel is using
+          this in a module, there is a pretty good chance it's actually the
+          wrong interface to use).  If you really need the symbol, please send a
+          mail to the linux kernel mailing list mentioning the symbol and why
+          you really need it, and what the merge plan to the mainline kernel for
+          your module is.
+
 config DEBUG_KERNEL
         bool "Kernel debugging"
         help