Patch "extcon: Remove potential problem when calling extcon_register_notifier()" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

extcon: Remove potential problem when calling extcon_register_notifier()

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
extcon-remove-potential-problem-when-calling-extcon_register_notifier.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Chanwoo Choi <[email protected]>
Date: Mon, 19 Dec 2016 21:02:33 +0900
Subject: extcon: Remove potential problem when calling extcon_register_notifier()

From: Chanwoo Choi <[email protected]>

[ Upstream commit 01b4c9a1ae07a25d208cad0da7dd288007a22984 ]

This patch removes the potential problem of extcon_register_notifier() when edev parameter is NULL. When edev is NULL, this function returns the first extcon device which includes the sepecific external connector of second paramter. But, it don't guarantee the same operation in all cases. To remove this confusion and potential problem, this patch fixes it.

---
 drivers/extcon/extcon.c |   35 ++++++++---------------------------
 1 file changed, 8 insertions(+), 27 deletions(-)

@@ -906,35 +906,16 @@ int extcon_register_notifier(struct extc
 	unsigned long flags;
 	int ret, idx = -EINVAL;
 
-	if (!nb)
+	if (!edev || !nb)
 		return -EINVAL;
 
-	if (edev) {
-		idx = find_cable_index_by_id(edev, id);
-		if (idx < 0)
-			return idx;
-
-		spin_lock_irqsave(&edev->lock, flags);
-		ret = raw_notifier_chain_register(&edev->nh[idx], nb);
-		spin_unlock_irqrestore(&edev->lock, flags);
-	} else {
-		struct extcon_dev *extd;
-
-		mutex_lock(&extcon_dev_list_lock);
-		list_for_each_entry(extd, &extcon_dev_list, entry) {
-			idx = find_cable_index_by_id(extd, id);
-			if (idx >= 0)
-				break;
-		}
-		mutex_unlock(&extcon_dev_list_lock);
-
-		if (idx >= 0) {
-			edev = extd;
-			return extcon_register_notifier(extd, id, nb);
-		} else {
-			ret = -ENODEV;
-		}
-	}
+	idx = find_cable_index_by_id(edev, id);
+	if (idx < 0)
+		return idx;
+
+	spin_lock_irqsave(&edev->lock, flags);
+	ret = raw_notifier_chain_register(&edev->nh[idx], nb);
+	spin_unlock_irqrestore(&edev->lock, flags);
 
 	return ret;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/extcon-remove-potential-problem-when-calling-extcon_register_notifier.patch queue-4.9/extcon-palmas-check-the-parent-instance-to-prevent-the-null.patch