extcon: Fix missing locking when [un]registering notifiers

Since extcon.c is using raw_notifiers it must protect the notifier
list itself when [un]registering notifiers to avoid the list changing while
extcon_update_state is walking the list (through raw_notifier_call_chain).

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
[cw00.choi: Apply this patch to extcon.c driver instead of old extcon-class.c]
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index 752ce1208428f19521c8a3535bc945c02c38267e..4c9f165e4a04e0b8a49ff36e42b8cfc078f2b8a6 100644 (file)
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -445,6 +445,9 @@ int extcon_register_interest(struct extcon_specific_cable_nb *obj,
                             const char *extcon_name, const char *cable_name,
                             struct notifier_block *nb)
 {
+       unsigned long flags;
+       int ret;
+
        if (!obj || !cable_name || !nb)
                return -EINVAL;
 
@@ -462,8 +465,11 @@ int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 
                obj->internal_nb.notifier_call = _call_per_cable;
 
-               return raw_notifier_chain_register(&obj->edev->nh,
+               spin_lock_irqsave(&obj->edev->lock, flags);
+               ret = raw_notifier_chain_register(&obj->edev->nh,
                                                  &obj->internal_nb);
+               spin_unlock_irqrestore(&obj->edev->lock, flags);
+               return ret;
        } else {
                struct class_dev_iter iter;
                struct extcon_dev *extd;
@@ -496,10 +502,17 @@ EXPORT_SYMBOL_GPL(extcon_register_interest);
  */
 int extcon_unregister_interest(struct extcon_specific_cable_nb *obj)
 {
+       unsigned long flags;
+       int ret;
+
        if (!obj)
                return -EINVAL;
 
-       return raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
+       spin_lock_irqsave(&obj->edev->lock, flags);
+       ret = raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
+       spin_unlock_irqrestore(&obj->edev->lock, flags);
+
+       return ret;
 }
 EXPORT_SYMBOL_GPL(extcon_unregister_interest);
 
@@ -516,7 +529,14 @@ EXPORT_SYMBOL_GPL(extcon_unregister_interest);
 int extcon_register_notifier(struct extcon_dev *edev,
                        struct notifier_block *nb)
 {
-       return raw_notifier_chain_register(&edev->nh, nb);
+       unsigned long flags;
+       int ret;
+
+       spin_lock_irqsave(&edev->lock, flags);
+       ret = raw_notifier_chain_register(&edev->nh, nb);
+       spin_unlock_irqrestore(&edev->lock, flags);
+
+       return ret;
 }
 EXPORT_SYMBOL_GPL(extcon_register_notifier);
 
@@ -528,7 +548,14 @@ EXPORT_SYMBOL_GPL(extcon_register_notifier);
 int extcon_unregister_notifier(struct extcon_dev *edev,
                        struct notifier_block *nb)
 {
-       return raw_notifier_chain_unregister(&edev->nh, nb);
+       unsigned long flags;
+       int ret;
+
+       spin_lock_irqsave(&edev->lock, flags);
+       ret = raw_notifier_chain_unregister(&edev->nh, nb);
+       spin_unlock_irqrestore(&edev->lock, flags);
+
+       return ret;
 }
 EXPORT_SYMBOL_GPL(extcon_unregister_notifier);