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Date: Thu, 24 Apr 2008 00:01:19 -0500
From: Rusty Russell <rusty@...tcorp.com.au>
To: linux-kernel@...r.kernel.org
Subject: [PATCH 3/6] 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@...tcorp.com.au>
---
kernel/module.c | 248
++++++++++++++++++++++++++++----------------------------
1 file changed, 126 insertions(+), 122 deletions(-)
diff -r 0cca514f2965 kernel/module.c
--- a/kernel/module.c Thu Apr 10 14:47:54 2008 +1000
+++ b/kernel/module.c Thu Apr 10 15:15:17 2008 +1000
@@ -165,131 +165,140 @@ static const struct kernel_symbol *looku
return NULL;
}
-static void printk_unused_warning(const char *name)
+static bool always_ok(bool gplok, bool warn, const char *name)
{
- printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
- "however this module is using it.\n", name);
- printk(KERN_WARNING "This symbol will go away in the future.\n");
- printk(KERN_WARNING "Please evalute if this is the right api to use, "
- "and if it really is, submit a report the linux kernel "
- "mailinglist together with submitting your code for "
- "inclusion.\n");
+ return true;
}
-/* Find a symbol, return value, crc and module which owns it */
-static unsigned long __find_symbol(const char *name,
- struct module **owner,
- const unsigned long **crc,
- int gplok)
+static bool printk_unused_warning(bool gplok, bool warn, const char *name)
+{
+ if (warn) {
+ printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
+ "however this module is using it.\n", name);
+ printk(KERN_WARNING
+ "This symbol will go away in the future.\n");
+ printk(KERN_WARNING
+ "Please evalute if this is the right api to use and if "
+ "it really is, submit a report the linux kernel "
+ "mailinglist together with submitting your code for "
+ "inclusion.\n");
+ }
+ return true;
+}
+
+static bool gpl_only_unused_warning(bool gplok, bool warn, const char *name)
+{
+ if (!gplok)
+ return false;
+ return printk_unused_warning(gplok, warn, name);
+}
+
+static bool gpl_only(bool gplok, bool warn, const char *name)
+{
+ return gplok;
+}
+
+static bool warn_if_not_gpl(bool gplok, bool warn, const char *name)
+{
+ if (!gplok && warn) {
+ printk(KERN_WARNING "Symbol %s is being used "
+ "by a non-GPL module, which will not "
+ "be allowed in the future\n", name);
+ printk(KERN_WARNING "Please see the file "
+ "Documentation/feature-removal-schedule.txt "
+ "in the kernel source tree for more details.\n");
+ }
+ return true;
+}
+
+struct symsearch {
+ const struct kernel_symbol *start, *stop;
+ const unsigned long *crcs;
+ bool (*check)(bool gplok, bool warn, const char *name);
+};
+
+/* Look through this array of symbol tables for a symbol match which
+ * passes the check function. */
+static const struct kernel_symbol *search_symarrays(const struct symsearch
*arr,
+ unsigned int num,
+ const char *name,
+ bool gplok,
+ bool warn,
+ const unsigned long **crc)
+{
+ unsigned int i;
+ const struct kernel_symbol *ks;
+
+ for (i = 0; i < num; i++) {
+ ks = lookup_symbol(name, arr[i].start, arr[i].stop);
+ if (!ks || !arr[i].check(gplok, warn, name))
+ continue;
+
+ if (crc)
+ *crc = symversion(arr[i].crcs, ks - arr[i].start);
+ return ks;
+ }
+ return NULL;
+}
+
+/* Find a symbol, return value, (optional) crc and (optional) module
+ * which owns it */
+static unsigned long find_symbol(const char *name,
+ struct module **owner,
+ const unsigned long **crc,
+ bool gplok,
+ bool warn)
{
struct module *mod;
const struct kernel_symbol *ks;
+ const struct symsearch arr[] = {
+ { __start___ksymtab, __stop___ksymtab, __start___kcrctab,
+ always_ok },
+ { __start___ksymtab_gpl, __stop___ksymtab_gpl,
+ __start___kcrctab_gpl, gpl_only },
+ { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
+ __start___kcrctab_gpl_future, warn_if_not_gpl },
+ { __start___ksymtab_unused, __stop___ksymtab_unused,
+ __start___kcrctab_unused, printk_unused_warning },
+ { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
+ __start___kcrctab_unused_gpl, gpl_only_unused_warning },
+ };
/* Core kernel first. */
- *owner = NULL;
- ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
+ ks = search_symarrays(arr, ARRAY_SIZE(arr), name, gplok, warn, crc);
if (ks) {
- *crc = symversion(__start___kcrctab, (ks - __start___ksymtab));
- return ks->value;
- }
- if (gplok) {
- ks = lookup_symbol(name, __start___ksymtab_gpl,
- __stop___ksymtab_gpl);
- if (ks) {
- *crc = symversion(__start___kcrctab_gpl,
- (ks - __start___ksymtab_gpl));
- return ks->value;
- }
- }
- ks = lookup_symbol(name, __start___ksymtab_gpl_future,
- __stop___ksymtab_gpl_future);
- if (ks) {
- if (!gplok) {
- printk(KERN_WARNING "Symbol %s is being used "
- "by a non-GPL module, which will not "
- "be allowed in the future\n", name);
- printk(KERN_WARNING "Please see the file "
- "Documentation/feature-removal-schedule.txt "
- "in the kernel source tree for more "
- "details.\n");
- }
- *crc = symversion(__start___kcrctab_gpl_future,
- (ks - __start___ksymtab_gpl_future));
- return ks->value;
- }
-
- ks = lookup_symbol(name, __start___ksymtab_unused,
- __stop___ksymtab_unused);
- if (ks) {
- printk_unused_warning(name);
- *crc = symversion(__start___kcrctab_unused,
- (ks - __start___ksymtab_unused));
- return ks->value;
- }
-
- if (gplok)
- ks = lookup_symbol(name, __start___ksymtab_unused_gpl,
- __stop___ksymtab_unused_gpl);
- if (ks) {
- printk_unused_warning(name);
- *crc = symversion(__start___kcrctab_unused_gpl,
- (ks - __start___ksymtab_unused_gpl));
+ if (owner)
+ *owner = NULL;
return ks->value;
}
/* Now try modules. */
list_for_each_entry(mod, &modules, list) {
- *owner = mod;
- ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
+ struct symsearch arr[] = {
+ { mod->syms, mod->syms + mod->num_syms, mod->crcs,
+ always_ok },
+ { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
+ mod->gpl_crcs, gpl_only },
+ { mod->gpl_future_syms,
+ mod->gpl_future_syms + mod->num_gpl_future_syms,
+ mod->gpl_future_crcs, warn_if_not_gpl },
+ { mod->unused_syms,
+ mod->unused_syms + mod->num_unused_syms,
+ mod->unused_crcs, printk_unused_warning },
+ { mod->unused_gpl_syms,
+ mod->unused_gpl_syms + mod->num_unused_gpl_syms,
+ mod->unused_gpl_crcs, gpl_only_unused_warning },
+ };
+
+ ks = search_symarrays(arr, ARRAY_SIZE(arr),
+ name, gplok, warn, crc);
if (ks) {
- *crc = symversion(mod->crcs, (ks - mod->syms));
- return ks->value;
- }
-
- if (gplok) {
- ks = lookup_symbol(name, mod->gpl_syms,
- mod->gpl_syms + mod->num_gpl_syms);
- if (ks) {
- *crc = symversion(mod->gpl_crcs,
- (ks - mod->gpl_syms));
- return ks->value;
- }
- }
- ks = lookup_symbol(name, mod->unused_syms, mod->unused_syms +
mod->num_unused_syms);
- if (ks) {
- printk_unused_warning(name);
- *crc = symversion(mod->unused_crcs, (ks - mod->unused_syms));
- return ks->value;
- }
-
- if (gplok) {
- ks = lookup_symbol(name, mod->unused_gpl_syms,
- mod->unused_gpl_syms + mod->num_unused_gpl_syms);
- if (ks) {
- printk_unused_warning(name);
- *crc = symversion(mod->unused_gpl_crcs,
- (ks - mod->unused_gpl_syms));
- return ks->value;
- }
- }
- ks = lookup_symbol(name, mod->gpl_future_syms,
- (mod->gpl_future_syms +
- mod->num_gpl_future_syms));
- if (ks) {
- if (!gplok) {
- printk(KERN_WARNING "Symbol %s is being used "
- "by a non-GPL module, which will not "
- "be allowed in the future\n", name);
- printk(KERN_WARNING "Please see the file "
- "Documentation/feature-removal-schedule.txt "
- "in the kernel source tree for more "
- "details.\n");
- }
- *crc = symversion(mod->gpl_future_crcs,
- (ks - mod->gpl_future_syms));
+ if (owner)
+ *owner = mod;
return ks->value;
}
}
+
DEBUGP("Failed to find symbol %s\n", name);
return -ENOENT;
}
@@ -778,10 +787,9 @@ void __symbol_put(const char *symbol)
void __symbol_put(const char *symbol)
{
struct module *owner;
- const unsigned long *crc;
preempt_disable();
- if (IS_ERR_VALUE(__find_symbol(symbol, &owner, &crc, 1)))
+ if (IS_ERR_VALUE(find_symbol(symbol, &owner, NULL, true, false)))
BUG();
module_put(owner);
preempt_enable();
@@ -925,13 +933,10 @@ static inline int check_modstruct_versio
struct module *mod)
{
const unsigned long *crc;
- struct module *owner;
- if (IS_ERR_VALUE(__find_symbol("struct_module",
- &owner, &crc, 1)))
+ if (IS_ERR_VALUE(find_symbol("struct_module", NULL, &crc, true, false)))
BUG();
- return check_version(sechdrs, versindex, "struct_module", mod,
- crc);
+ return check_version(sechdrs, versindex, "struct_module", mod, crc);
}
/* First part is kernel version, which we ignore. */
@@ -975,8 +980,8 @@ static unsigned long resolve_symbol(Elf_
unsigned long ret;
const unsigned long *crc;
- ret = __find_symbol(name, &owner, &crc,
- !(mod->taints & TAINT_PROPRIETARY_MODULE));
+ ret = find_symbol(name, &owner, &crc,
+ !(mod->taints & TAINT_PROPRIETARY_MODULE), true);
if (!IS_ERR_VALUE(ret)) {
/* use_module can fail due to OOM,
or module initialization or unloading */
@@ -1377,10 +1382,9 @@ void *__symbol_get(const char *symbol)
{
struct module *owner;
unsigned long value;
- const unsigned long *crc;
preempt_disable();
- value = __find_symbol(symbol, &owner, &crc, 1);
+ value = find_symbol(symbol, &owner, NULL, true, true);
if (IS_ERR_VALUE(value))
value = 0;
else if (strong_try_module_get(owner))
@@ -1403,16 +1407,16 @@ static int verify_export_symbols(struct
const unsigned long *crc;
for (i = 0; i < mod->num_syms; i++)
- if (!IS_ERR_VALUE(__find_symbol(mod->syms[i].name,
- &owner, &crc, 1))) {
+ if (!IS_ERR_VALUE(find_symbol(mod->syms[i].name,
+ &owner, &crc, true, false))) {
name = mod->syms[i].name;
ret = -ENOEXEC;
goto dup;
}
for (i = 0; i < mod->num_gpl_syms; i++)
- if (!IS_ERR_VALUE(__find_symbol(mod->gpl_syms[i].name,
- &owner, &crc, 1))) {
+ if (!IS_ERR_VALUE(find_symbol(mod->gpl_syms[i].name,
+ &owner, &crc, true, false))) {
name = mod->gpl_syms[i].name;
ret = -ENOEXEC;
goto dup;
--
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