linux-kernel - [PATCH v2 1/2] modules: split part of complete_formation() into prepare_coming

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Date:	Fri, 11 Mar 2016 15:03:47 -0500
From:	Jessica Yu <jeyu@...hat.com>
To:	Josh Poimboeuf <jpoimboe@...hat.com>,
	Seth Jennings <sjenning@...hat.com>,
	Jiri Kosina <jikos@...nel.org>,
	Vojtech Pavlik <vojtech@...e.com>,
	Miroslav Benes <mbenes@...e.cz>,
	Petr Mladek <pmladek@...e.com>,
	Rusty Russell <rusty@...tcorp.com.au>
Cc:	Steven Rostedt <rostedt@...dmis.org>,
	live-patching@...r.kernel.org, linux-kernel@...r.kernel.org,
	Jessica Yu <jeyu@...hat.com>
Subject: [PATCH v2 1/2] modules: split part of complete_formation() into prepare_coming_module()

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@...hat.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@...hat.com>
Acked-by: Rusty Russell <rusty@...tcorp.com.au>
---
 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