[PATCH 11/13] module: pass struct find_symbol_args to find_symbol

Christoph Hellwig
2021-01-21T08:15:51Z

Simplify the calling convention by passing the find_symbol_args structure
to find_symbol instead of initializing it inside the function.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
kernel/module.c | 113 ++++++++++++++++++++++--------------------------
1 file changed, 52 insertions(+), 61 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 644dda52dae38c..7a88b71736ff5c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -536,12 +536,7 @@ static bool find_exported_symbol_in_section(const struct symsearch *syms,
* Find an exported symbol and return it, along with, (optional) crc and
* (optional) module which owns it. Needs preempt disabled or module_mutex.
*/
-static const struct kernel_symbol *find_symbol(const char *name,
- struct module **owner,
- const s32 **crc,
- enum mod_license *license,
- bool gplok,
- bool warn)
+static bool find_symbol(struct find_symbol_arg *fsa)
{
static const struct symsearch arr[] = {
{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
@@ -561,19 +556,14 @@ static const struct kernel_symbol *find_symbol(const char *name,
GPL_ONLY, true },
#endif
};
- struct find_symbol_arg fsa = {
- .name = name,
- .gplok = gplok,
- .warn = warn,
- };
struct module *mod;
unsigned int i;

module_assert_mutex_or_preempt();

for (i = 0; i < ARRAY_SIZE(arr); i++)
- if (find_exported_symbol_in_section(&arr[i], NULL, &fsa))
- goto found;
+ if (find_exported_symbol_in_section(&arr[i], NULL, fsa))
+ return true;

list_for_each_entry_rcu(mod, &modules, list,
lockdep_is_held(&module_mutex)) {
@@ -603,21 +593,12 @@ static const struct kernel_symbol *find_symbol(const char *name,
continue;

for (i = 0; i < ARRAY_SIZE(arr); i++)
- if (find_exported_symbol_in_section(&arr[i], mod, &fsa))
- goto found;
+ if (find_exported_symbol_in_section(&arr[i], mod, fsa))
+ return true;
}

- pr_debug("Failed to find symbol %s\n", name);
- return NULL;
-
-found:
- if (owner)
- *owner = fsa.owner;
- if (crc)
- *crc = fsa.crc;
- if (license)
- *license = fsa.license;
- return fsa.sym;
+ pr_debug("Failed to find symbol %s\n", fsa->name);
+ return false;
}

/*
@@ -1107,12 +1088,15 @@ static inline void print_unload_info(struct seq_file *m, struct module *mod)

void __symbol_put(const char *symbol)
{
- struct module *owner;
+ struct find_symbol_arg fsa = {
+ .name = symbol,
+ .gplok = true,
+ };

preempt_disable();
- if (!find_symbol(symbol, &owner, NULL, NULL, true, false))
+ if (!find_symbol(&fsa))
BUG();
- module_put(owner);
+ module_put(fsa.owner);
preempt_enable();
}
EXPORT_SYMBOL(__symbol_put);
@@ -1381,19 +1365,22 @@ static int check_version(const struct load_info *info,
static inline int check_modstruct_version(const struct load_info *info,
struct module *mod)
{
- const s32 *crc;
+ struct find_symbol_arg fsa = {
+ .name = "module_layout",
+ .gplok = true,
+ };

/*
* Since this should be found in kernel (which can't be removed), no
* locking is necessary -- use preempt_disable() to placate lockdep.
*/
preempt_disable();
- if (!find_symbol("module_layout", NULL, &crc, NULL, true, false)) {
+ if (!find_symbol(&fsa)) {
preempt_enable();
BUG();
}
preempt_enable();
- return check_version(info, "module_layout", mod, crc);
+ return check_version(info, "module_layout", mod, fsa.crc);
}

/* First part is kernel version, which we ignore if module has crcs. */
@@ -1487,10 +1474,11 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
const char *name,
char ownername[])
{
- struct module *owner;
- const struct kernel_symbol *sym;
- const s32 *crc;
- enum mod_license license;
+ struct find_symbol_arg fsa = {
+ .name = name,
+ .gplok = !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)),
+ .warn = true,
+ };
int err;

/*
@@ -1500,42 +1488,40 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
*/
sched_annotate_sleep();
mutex_lock(&module_mutex);
- sym = find_symbol(name, &owner, &crc, &license,
- !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
- if (!sym)
+ if (!find_symbol(&fsa))
goto unlock;

- if (license == GPL_ONLY)
+ if (fsa.license == GPL_ONLY)
mod->using_gplonly_symbols = true;

- if (!inherit_taint(mod, owner)) {
- sym = NULL;
+ if (!inherit_taint(mod, fsa.owner)) {
+ fsa.sym = NULL;
goto getname;
}

- if (!check_version(info, name, mod, crc)) {
- sym = ERR_PTR(-EINVAL);
+ if (!check_version(info, name, mod, fsa.crc)) {
+ fsa.sym = ERR_PTR(-EINVAL);
goto getname;
}

- err = verify_namespace_is_imported(info, sym, mod);
+ err = verify_namespace_is_imported(info, fsa.sym, mod);
if (err) {
- sym = ERR_PTR(err);
+ fsa.sym = ERR_PTR(err);
goto getname;
}

- err = ref_module(mod, owner);
+ err = ref_module(mod, fsa.owner);
if (err) {
- sym = ERR_PTR(err);
+ fsa.sym = ERR_PTR(err);
goto getname;
}

getname:
/* We must make copy under the lock if we failed to get ref. */
- strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
+ strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN);
unlock:
mutex_unlock(&module_mutex);
- return sym;
+ return fsa.sym;
}

static const struct kernel_symbol *
@@ -2296,16 +2282,19 @@ static void free_module(struct module *mod)

void *__symbol_get(const char *symbol)
{
- struct module *owner;
- const struct kernel_symbol *sym;
+ struct find_symbol_arg fsa = {
+ .name = symbol,
+ .gplok = true,
+ .warn = true,
+ };

preempt_disable();
- sym = find_symbol(symbol, &owner, NULL, NULL, true, true);
- if (sym && strong_try_module_get(owner))
- sym = NULL;
+ if (!find_symbol(&fsa) || !strong_try_module_get(fsa.owner)) {
+ preempt_enable();
+ return NULL;
+ }
preempt_enable();
-
- return sym ? (void *)kernel_symbol_value(sym) : NULL;
+ return (void *)kernel_symbol_value(fsa.sym);
}
EXPORT_SYMBOL_GPL(__symbol_get);

@@ -2318,7 +2307,6 @@ EXPORT_SYMBOL_GPL(__symbol_get);
static int verify_exported_symbols(struct module *mod)
{
unsigned int i;
- struct module *owner;
const struct kernel_symbol *s;
struct {
const struct kernel_symbol *sym;
@@ -2335,12 +2323,15 @@ static int verify_exported_symbols(struct module *mod)

for (i = 0; i < ARRAY_SIZE(arr); i++) {
for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
- if (find_symbol(kernel_symbol_name(s), &owner, NULL,
- NULL, true, false)) {
+ struct find_symbol_arg fsa = {
+ .name = kernel_symbol_name(s),
+ .gplok = true,
+ };
+ if (find_symbol(&fsa)) {
pr_err("%s: exports duplicate symbol %s"
" (owned by %s)\n",
mod->name, kernel_symbol_name(s),
- module_name(owner));
+ module_name(fsa.owner));
return -ENOEXEC;
}
}
--
2.29.2