module: neaten __find_symbol, rename to find_symbol
__find_symbol() has grown over time: there are now 5 different arrays of symbols it traverses. It also shouldn't print out a warning on some calls (ie. verify_symbol which simply checks for name clashes, and __symbol_put which checks for bugs). 1) Rename to find_symbol: no need for underscores. 2) Use bool and add "warn" parameter to suppress warnings. 3) Make table-driven rather than open coded. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
parent
ea01e798e2
commit
ad9546c991
246
kernel/module.c
246
kernel/module.c
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@ -164,131 +164,140 @@ static const struct kernel_symbol *lookup_symbol(const char *name,
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return NULL;
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}
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static void printk_unused_warning(const char *name)
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static bool always_ok(bool gplok, bool warn, const char *name)
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{
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printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
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"however this module is using it.\n", name);
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printk(KERN_WARNING "This symbol will go away in the future.\n");
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printk(KERN_WARNING "Please evalute if this is the right api to use, "
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"and if it really is, submit a report the linux kernel "
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"mailinglist together with submitting your code for "
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"inclusion.\n");
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return true;
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}
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/* Find a symbol, return value, crc and module which owns it */
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static unsigned long __find_symbol(const char *name,
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struct module **owner,
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const unsigned long **crc,
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int gplok)
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static bool printk_unused_warning(bool gplok, bool warn, const char *name)
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{
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if (warn) {
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printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
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"however this module is using it.\n", name);
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printk(KERN_WARNING
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"This symbol will go away in the future.\n");
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printk(KERN_WARNING
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"Please evalute if this is the right api to use and if "
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"it really is, submit a report the linux kernel "
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"mailinglist together with submitting your code for "
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"inclusion.\n");
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}
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return true;
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}
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static bool gpl_only_unused_warning(bool gplok, bool warn, const char *name)
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{
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if (!gplok)
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return false;
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return printk_unused_warning(gplok, warn, name);
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}
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static bool gpl_only(bool gplok, bool warn, const char *name)
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{
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return gplok;
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}
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static bool warn_if_not_gpl(bool gplok, bool warn, const char *name)
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{
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if (!gplok && warn) {
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printk(KERN_WARNING "Symbol %s is being used "
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"by a non-GPL module, which will not "
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"be allowed in the future\n", name);
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printk(KERN_WARNING "Please see the file "
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"Documentation/feature-removal-schedule.txt "
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"in the kernel source tree for more details.\n");
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}
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return true;
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}
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struct symsearch {
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const struct kernel_symbol *start, *stop;
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const unsigned long *crcs;
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bool (*check)(bool gplok, bool warn, const char *name);
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};
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/* Look through this array of symbol tables for a symbol match which
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* passes the check function. */
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static const struct kernel_symbol *search_symarrays(const struct symsearch *arr,
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unsigned int num,
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const char *name,
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bool gplok,
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bool warn,
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const unsigned long **crc)
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{
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unsigned int i;
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const struct kernel_symbol *ks;
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for (i = 0; i < num; i++) {
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ks = lookup_symbol(name, arr[i].start, arr[i].stop);
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if (!ks || !arr[i].check(gplok, warn, name))
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continue;
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if (crc)
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*crc = symversion(arr[i].crcs, ks - arr[i].start);
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return ks;
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}
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return NULL;
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}
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/* Find a symbol, return value, (optional) crc and (optional) module
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* which owns it */
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static unsigned long find_symbol(const char *name,
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struct module **owner,
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const unsigned long **crc,
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bool gplok,
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bool warn)
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{
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struct module *mod;
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const struct kernel_symbol *ks;
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const struct symsearch arr[] = {
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{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
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always_ok },
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{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
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__start___kcrctab_gpl, gpl_only },
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{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
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__start___kcrctab_gpl_future, warn_if_not_gpl },
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{ __start___ksymtab_unused, __stop___ksymtab_unused,
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__start___kcrctab_unused, printk_unused_warning },
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{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
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__start___kcrctab_unused_gpl, gpl_only_unused_warning },
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};
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/* Core kernel first. */
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*owner = NULL;
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ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
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ks = search_symarrays(arr, ARRAY_SIZE(arr), name, gplok, warn, crc);
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if (ks) {
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*crc = symversion(__start___kcrctab, (ks - __start___ksymtab));
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return ks->value;
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}
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if (gplok) {
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ks = lookup_symbol(name, __start___ksymtab_gpl,
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__stop___ksymtab_gpl);
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if (ks) {
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*crc = symversion(__start___kcrctab_gpl,
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(ks - __start___ksymtab_gpl));
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return ks->value;
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}
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}
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ks = lookup_symbol(name, __start___ksymtab_gpl_future,
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__stop___ksymtab_gpl_future);
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if (ks) {
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if (!gplok) {
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printk(KERN_WARNING "Symbol %s is being used "
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"by a non-GPL module, which will not "
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"be allowed in the future\n", name);
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printk(KERN_WARNING "Please see the file "
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"Documentation/feature-removal-schedule.txt "
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"in the kernel source tree for more "
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"details.\n");
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}
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*crc = symversion(__start___kcrctab_gpl_future,
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(ks - __start___ksymtab_gpl_future));
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return ks->value;
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}
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ks = lookup_symbol(name, __start___ksymtab_unused,
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__stop___ksymtab_unused);
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if (ks) {
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printk_unused_warning(name);
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*crc = symversion(__start___kcrctab_unused,
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(ks - __start___ksymtab_unused));
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return ks->value;
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}
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if (gplok)
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ks = lookup_symbol(name, __start___ksymtab_unused_gpl,
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__stop___ksymtab_unused_gpl);
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if (ks) {
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printk_unused_warning(name);
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*crc = symversion(__start___kcrctab_unused_gpl,
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(ks - __start___ksymtab_unused_gpl));
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if (owner)
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*owner = NULL;
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return ks->value;
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}
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/* Now try modules. */
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list_for_each_entry(mod, &modules, list) {
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*owner = mod;
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ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
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if (ks) {
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*crc = symversion(mod->crcs, (ks - mod->syms));
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return ks->value;
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}
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struct symsearch arr[] = {
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{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
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always_ok },
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{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
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mod->gpl_crcs, gpl_only },
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{ mod->gpl_future_syms,
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mod->gpl_future_syms + mod->num_gpl_future_syms,
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mod->gpl_future_crcs, warn_if_not_gpl },
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{ mod->unused_syms,
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mod->unused_syms + mod->num_unused_syms,
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mod->unused_crcs, printk_unused_warning },
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{ mod->unused_gpl_syms,
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mod->unused_gpl_syms + mod->num_unused_gpl_syms,
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mod->unused_gpl_crcs, gpl_only_unused_warning },
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};
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if (gplok) {
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ks = lookup_symbol(name, mod->gpl_syms,
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mod->gpl_syms + mod->num_gpl_syms);
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if (ks) {
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*crc = symversion(mod->gpl_crcs,
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(ks - mod->gpl_syms));
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return ks->value;
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}
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}
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ks = lookup_symbol(name, mod->unused_syms, mod->unused_syms + mod->num_unused_syms);
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ks = search_symarrays(arr, ARRAY_SIZE(arr),
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name, gplok, warn, crc);
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if (ks) {
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printk_unused_warning(name);
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*crc = symversion(mod->unused_crcs, (ks - mod->unused_syms));
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return ks->value;
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}
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if (gplok) {
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ks = lookup_symbol(name, mod->unused_gpl_syms,
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mod->unused_gpl_syms + mod->num_unused_gpl_syms);
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if (ks) {
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printk_unused_warning(name);
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*crc = symversion(mod->unused_gpl_crcs,
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(ks - mod->unused_gpl_syms));
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return ks->value;
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}
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}
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ks = lookup_symbol(name, mod->gpl_future_syms,
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(mod->gpl_future_syms +
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mod->num_gpl_future_syms));
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if (ks) {
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if (!gplok) {
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printk(KERN_WARNING "Symbol %s is being used "
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"by a non-GPL module, which will not "
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"be allowed in the future\n", name);
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printk(KERN_WARNING "Please see the file "
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"Documentation/feature-removal-schedule.txt "
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"in the kernel source tree for more "
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"details.\n");
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}
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*crc = symversion(mod->gpl_future_crcs,
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(ks - mod->gpl_future_syms));
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if (owner)
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*owner = mod;
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return ks->value;
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}
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}
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DEBUGP("Failed to find symbol %s\n", name);
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return -ENOENT;
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}
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@ -777,10 +786,9 @@ static void print_unload_info(struct seq_file *m, struct module *mod)
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void __symbol_put(const char *symbol)
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{
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struct module *owner;
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const unsigned long *crc;
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preempt_disable();
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if (IS_ERR_VALUE(__find_symbol(symbol, &owner, &crc, 1)))
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if (IS_ERR_VALUE(find_symbol(symbol, &owner, NULL, true, false)))
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BUG();
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module_put(owner);
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preempt_enable();
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@ -924,13 +932,10 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
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struct module *mod)
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{
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const unsigned long *crc;
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struct module *owner;
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if (IS_ERR_VALUE(__find_symbol("struct_module",
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&owner, &crc, 1)))
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if (IS_ERR_VALUE(find_symbol("struct_module", NULL, &crc, true, false)))
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BUG();
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return check_version(sechdrs, versindex, "struct_module", mod,
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crc);
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return check_version(sechdrs, versindex, "struct_module", mod, crc);
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}
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/* First part is kernel version, which we ignore. */
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@ -974,8 +979,8 @@ static unsigned long resolve_symbol(Elf_Shdr *sechdrs,
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unsigned long ret;
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const unsigned long *crc;
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ret = __find_symbol(name, &owner, &crc,
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!(mod->taints & TAINT_PROPRIETARY_MODULE));
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ret = find_symbol(name, &owner, &crc,
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!(mod->taints & TAINT_PROPRIETARY_MODULE), true);
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if (!IS_ERR_VALUE(ret)) {
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/* use_module can fail due to OOM,
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or module initialization or unloading */
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@ -1376,10 +1381,9 @@ void *__symbol_get(const char *symbol)
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{
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struct module *owner;
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unsigned long value;
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const unsigned long *crc;
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preempt_disable();
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value = __find_symbol(symbol, &owner, &crc, 1);
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value = find_symbol(symbol, &owner, NULL, true, true);
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if (IS_ERR_VALUE(value))
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value = 0;
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else if (strong_try_module_get(owner))
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@ -1402,16 +1406,16 @@ static int verify_export_symbols(struct module *mod)
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const unsigned long *crc;
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for (i = 0; i < mod->num_syms; i++)
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if (!IS_ERR_VALUE(__find_symbol(mod->syms[i].name,
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&owner, &crc, 1))) {
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if (!IS_ERR_VALUE(find_symbol(mod->syms[i].name,
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&owner, &crc, true, false))) {
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name = mod->syms[i].name;
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ret = -ENOEXEC;
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goto dup;
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}
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for (i = 0; i < mod->num_gpl_syms; i++)
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if (!IS_ERR_VALUE(__find_symbol(mod->gpl_syms[i].name,
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&owner, &crc, 1))) {
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if (!IS_ERR_VALUE(find_symbol(mod->gpl_syms[i].name,
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&owner, &crc, true, false))) {
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name = mod->gpl_syms[i].name;
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ret = -ENOEXEC;
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goto dup;
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