[PATCH v2 1/2] modules: split part of complete_formation() into prepare_coming_module()

From: Jessica Yu
Date: Fri Mar 11 2016 - 15:04:17 EST


Put all actions in complete_formation() that are performed after
module->state is set to MODULE_STATE_COMING into a separate function
prepare_coming_module(). This split prepares for the removal of the
livepatch module notifiers in favor of hard-coding function calls to
klp_module_{coming,going} in the module loader.

The complete_formation -> prepare_coming_module split will also make error
handling easier since we can jump to the appropriate error label to do any
module GOING cleanup after all the COMING-actions have completed.

Signed-off-by: Jessica Yu <jeyu@xxxxxxxxxx>
Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Acked-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
---
kernel/module.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 87cfeb2..1981ae0 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3312,6 +3312,14 @@ out_unlocked:
return err;
}

+static int prepare_coming_module(struct module *mod)
+{
+ ftrace_module_enable(mod);
+ blocking_notifier_call_chain(&module_notify_list,
+ MODULE_STATE_COMING, mod);
+ return 0;
+}
+
static int complete_formation(struct module *mod, struct load_info *info)
{
int err;
@@ -3335,9 +3343,6 @@ static int complete_formation(struct module *mod, struct load_info *info)
mod->state = MODULE_STATE_COMING;
mutex_unlock(&module_mutex);

- ftrace_module_enable(mod);
- blocking_notifier_call_chain(&module_notify_list,
- MODULE_STATE_COMING, mod);
return 0;

out:
@@ -3459,13 +3464,17 @@ static int load_module(struct load_info *info, const char __user *uargs,
if (err)
goto ddebug_cleanup;

+ err = prepare_coming_module(mod);
+ if (err)
+ goto bug_cleanup;
+
/* Module is ready to execute: parsing args may do that. */
after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
-32768, 32767, mod,
unknown_module_param_cb);
if (IS_ERR(after_dashes)) {
err = PTR_ERR(after_dashes);
- goto bug_cleanup;
+ goto coming_cleanup;
} else if (after_dashes) {
pr_warn("%s: parameters '%s' after `--' ignored\n",
mod->name, after_dashes);
@@ -3474,7 +3483,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
/* Link in to syfs. */
err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
if (err < 0)
- goto bug_cleanup;
+ goto coming_cleanup;

/* Get rid of temporary copy. */
free_copy(info);
@@ -3484,15 +3493,16 @@ static int load_module(struct load_info *info, const char __user *uargs,

return do_init_module(mod);

+ coming_cleanup:
+ blocking_notifier_call_chain(&module_notify_list,
+ MODULE_STATE_GOING, mod);
+
bug_cleanup:
/* module_bug_cleanup needs module_mutex protection */
mutex_lock(&module_mutex);
module_bug_cleanup(mod);
mutex_unlock(&module_mutex);

- blocking_notifier_call_chain(&module_notify_list,
- MODULE_STATE_GOING, mod);
-
/* we can't deallocate the module until we clear memory protection */
module_disable_ro(mod);
module_disable_nx(mod);
--
2.4.3