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Shrink struct module: CONFIG_UNUSED_SYMBOLS ifdefs
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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 <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>
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@rustyrussell
Denys Vlasenko authored and rustyrussell committed Jul 22, 2008
1 parent af54068 commit f7f5b67
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Showing 3 changed files with 38 additions and 17 deletions.
2 changes: 2 additions & 0 deletions include/linux/module.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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;
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4 changes: 2 additions & 2 deletions init/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -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"
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49 changes: 34 additions & 15 deletions kernel/module.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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))
Expand All @@ -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,
Expand All @@ -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))
Expand Down Expand Up @@ -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);
Expand All @@ -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);
Expand Down Expand Up @@ -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++) {
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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");
Expand Down Expand Up @@ -2049,28 +2063,33 @@ 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;
mod->unused_gpl_syms = (void *)sechdrs[unusedgplindex].sh_addr;
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)
Expand Down

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