Shrink struct module: CONFIG_UNUSED_SYMBOLS ifdefs

module.c and module.h conatains code for finding
exported symbols which are declared with EXPORT_UNUSED_SYMBOL,
and this code is compiled in even if CONFIG_UNUSED_SYMBOLS is not set
and thus there can be no EXPORT_UNUSED_SYMBOLs in modules anyway
(because EXPORT_UNUSED_SYMBOL(x) are compiled out to nothing then).

This patch adds required #ifdefs.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

3 files changed, 38 insertions, 17 deletions

diff --git a/include/linux/module.h b/include/linux/module.h
index 63f0eb69e214..a860a2c1f379 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -257,6 +257,7 @@ struct module
         const struct kernel_symbol *gpl_syms;
         const unsigned long *gpl_crcs;
 
+#ifdef CONFIG_UNUSED_SYMBOLS
         /* unused exported symbols. */
         const struct kernel_symbol *unused_syms;
         const unsigned long *unused_crcs;
@@ -266,6 +267,7 @@ struct module
         unsigned int num_unused_gpl_syms;
         const struct kernel_symbol *unused_gpl_syms;
         const unsigned long *unused_gpl_crcs;
+#endif
 
         /* symbols that will be GPL-only in the near future. */
         const struct kernel_symbol *gpl_future_syms;
diff --git a/init/Kconfig b/init/Kconfig
index 6199d1120900..c8578f9ee31d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -856,8 +856,8 @@ config MODULE_UNLOAD
         help
           Without this option you will not be able to unload any
           modules (note that some modules may not be unloadable
-          anyway), which makes your kernel slightly smaller and
-          simpler.  If unsure, say Y.
+          anyway), which makes your kernel smaller, faster
+          and simpler.  If unsure, say Y.
 
 config MODULE_FORCE_UNLOAD
         bool "Forced module unloading"
diff --git a/kernel/module.c b/kernel/module.c
index c51c089c666e..ea9580521eb1 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -134,17 +134,19 @@ extern const struct kernel_symbol __start___ksymtab_gpl[];
 extern const struct kernel_symbol __stop___ksymtab_gpl[];
 extern const struct kernel_symbol __start___ksymtab_gpl_future[];
 extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
-extern const struct kernel_symbol __start___ksymtab_unused[];
-extern const struct kernel_symbol __stop___ksymtab_unused[];
-extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
-extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
 extern const struct kernel_symbol __start___ksymtab_gpl_future[];
 extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
 extern const unsigned long __start___kcrctab[];
 extern const unsigned long __start___kcrctab_gpl[];
 extern const unsigned long __start___kcrctab_gpl_future[];
+#ifdef CONFIG_UNUSED_SYMBOLS
+extern const struct kernel_symbol __start___ksymtab_unused[];
+extern const struct kernel_symbol __stop___ksymtab_unused[];
+extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
+extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
 extern const unsigned long __start___kcrctab_unused[];
 extern const unsigned long __start___kcrctab_unused_gpl[];
+#endif
 
 #ifndef CONFIG_MODVERSIONS
 #define symversion(base, idx) NULL
@@ -198,12 +200,14 @@ static bool each_symbol(bool (*fn)(const struct symsearch *arr,
                 { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
                   __start___kcrctab_gpl_future,
                   WILL_BE_GPL_ONLY, false },
+#ifdef CONFIG_UNUSED_SYMBOLS
                 { __start___ksymtab_unused, __stop___ksymtab_unused,
                   __start___kcrctab_unused,
                   NOT_GPL_ONLY, true },
                 { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
                   __start___kcrctab_unused_gpl,
                   GPL_ONLY, true },
+#endif
         };
 
         if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
@@ -220,6 +224,7 @@ static bool each_symbol(bool (*fn)(const struct symsearch *arr,
                           mod->gpl_future_syms + mod->num_gpl_future_syms,
                           mod->gpl_future_crcs,
                           WILL_BE_GPL_ONLY, false },
+#ifdef CONFIG_UNUSED_SYMBOLS
                         { mod->unused_syms,
                           mod->unused_syms + mod->num_unused_syms,
                           mod->unused_crcs,
@@ -228,6 +233,7 @@ static bool each_symbol(bool (*fn)(const struct symsearch *arr,
                           mod->unused_gpl_syms + mod->num_unused_gpl_syms,
                           mod->unused_gpl_crcs,
                           GPL_ONLY, true },
+#endif
                 };
 
                 if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
@@ -270,6 +276,7 @@ static bool find_symbol_in_section(const struct symsearch *syms,
                 }
         }
 
+#ifdef CONFIG_UNUSED_SYMBOLS
         if (syms->unused && fsa->warn) {
                 printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
                        "however this module is using it.\n", fsa->name);
@@ -281,6 +288,7 @@ static bool find_symbol_in_section(const struct symsearch *syms,
                        "mailinglist together with submitting your code for "
                        "inclusion.\n");
         }
+#endif
 
         fsa->owner = owner;
         fsa->crc = symversion(syms->crcs, symnum);
@@ -1476,8 +1484,10 @@ static int verify_export_symbols(struct module *mod)
                 { mod->syms, mod->num_syms },
                 { mod->gpl_syms, mod->num_gpl_syms },
                 { mod->gpl_future_syms, mod->num_gpl_future_syms },
+#ifdef CONFIG_UNUSED_SYMBOLS
                 { mod->unused_syms, mod->num_unused_syms },
                 { mod->unused_gpl_syms, mod->num_unused_gpl_syms },
+#endif
         };
 
         for (i = 0; i < ARRAY_SIZE(arr); i++) {
@@ -1795,10 +1805,12 @@ static struct module *load_module(void __user *umod,
         unsigned int gplfutureindex;
         unsigned int gplfuturecrcindex;
         unsigned int unwindex = 0;
+#ifdef CONFIG_UNUSED_SYMBOLS
         unsigned int unusedindex;
         unsigned int unusedcrcindex;
         unsigned int unusedgplindex;
         unsigned int unusedgplcrcindex;
+#endif
         unsigned int markersindex;
         unsigned int markersstringsindex;
         struct module *mod;
@@ -1881,13 +1893,15 @@ static struct module *load_module(void __user *umod,
         exportindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab");
         gplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl");
         gplfutureindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl_future");
-        unusedindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused");
-        unusedgplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused_gpl");
         crcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab");
         gplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl");
         gplfuturecrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl_future");
+#ifdef CONFIG_UNUSED_SYMBOLS
+        unusedindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused");
+        unusedgplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused_gpl");
         unusedcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_unused");
         unusedgplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_unused_gpl");
+#endif
         setupindex = find_sec(hdr, sechdrs, secstrings, "__param");
         exindex = find_sec(hdr, sechdrs, secstrings, "__ex_table");
         obsparmindex = find_sec(hdr, sechdrs, secstrings, "__obsparm");
@@ -2049,14 +2063,15 @@ static struct module *load_module(void __user *umod,
                 mod->gpl_crcs = (void *)sechdrs[gplcrcindex].sh_addr;
         mod->num_gpl_future_syms = sechdrs[gplfutureindex].sh_size /
                                         sizeof(*mod->gpl_future_syms);
-        mod->num_unused_syms = sechdrs[unusedindex].sh_size /
-                                        sizeof(*mod->unused_syms);
-        mod->num_unused_gpl_syms = sechdrs[unusedgplindex].sh_size /
-                                        sizeof(*mod->unused_gpl_syms);
         mod->gpl_future_syms = (void *)sechdrs[gplfutureindex].sh_addr;
         if (gplfuturecrcindex)
                 mod->gpl_future_crcs = (void *)sechdrs[gplfuturecrcindex].sh_addr;
 
+#ifdef CONFIG_UNUSED_SYMBOLS
+        mod->num_unused_syms = sechdrs[unusedindex].sh_size /
+                                        sizeof(*mod->unused_syms);
+        mod->num_unused_gpl_syms = sechdrs[unusedgplindex].sh_size /
+                                        sizeof(*mod->unused_gpl_syms);
         mod->unused_syms = (void *)sechdrs[unusedindex].sh_addr;
         if (unusedcrcindex)
                 mod->unused_crcs = (void *)sechdrs[unusedcrcindex].sh_addr;
@@ -2064,13 +2079,17 @@ static struct module *load_module(void __user *umod,
         if (unusedgplcrcindex)
                 mod->unused_gpl_crcs
                         = (void *)sechdrs[unusedgplcrcindex].sh_addr;
+#endif
 
 #ifdef CONFIG_MODVERSIONS
-        if ((mod->num_syms && !crcindex) ||
-            (mod->num_gpl_syms && !gplcrcindex) ||
-            (mod->num_gpl_future_syms && !gplfuturecrcindex) ||
-            (mod->num_unused_syms && !unusedcrcindex) ||
-            (mod->num_unused_gpl_syms && !unusedgplcrcindex)) {
+        if ((mod->num_syms && !crcindex)
+            || (mod->num_gpl_syms && !gplcrcindex)
+            || (mod->num_gpl_future_syms && !gplfuturecrcindex)
+#ifdef CONFIG_UNUSED_SYMBOLS
+            || (mod->num_unused_syms && !unusedcrcindex)
+            || (mod->num_unused_gpl_syms && !unusedgplcrcindex)
+#endif
+                ) {
                 printk(KERN_WARNING "%s: No versions for exported symbols.\n", mod->name);
                 err = try_to_force_load(mod, "nocrc");
                 if (err)