usb: typec: class: fix typec_altmode_put_partner to put plugs

commit 5962ded7 upstream.

When typec_altmode_put_partner is called by a plug altmode upon release,
the port altmode the plug belongs to will not remove its reference to the
plug. The check to see if the altmode being released is a plug evaluates
against the released altmode's partner instead of the calling altmode, so
change adev in typec_altmode_put_partner to properly refer to the altmode
being released.

Because typec_altmode_set_partner calls get_device() on the port altmode,
add partner_adev that points to the port altmode in typec_put_partner to
call put_device() on. typec_altmode_set_partner is not called for port
altmodes, so add a check in typec_altmode_release to prevent
typec_altmode_put_partner() calls on port altmode release.

Fixes: 8a37d87d ("usb: typec: Bus type for alternate modes")
Cc:  <stable@vger.kernel.org>
Co-developed-by: Christian A. Ehrhardt <lk@c--e.de>
Signed-off-by: Christian A. Ehrhardt <lk@c--e.de>
Signed-off-by: RD Babiera <rdbabiera@google.com>
Tested-by: Christian A. Ehrhardt <lk@c--e.de>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240103181754.2492492-2-rdbabiera@google.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/class.c

@@ -189,11 +189,13 @@ static void typec_altmode_put_partner(struct altmode *altmode)
 {
 	struct altmode *partner = altmode->partner;
 	struct typec_altmode *adev;
+	struct typec_altmode *partner_adev;
 
 	if (!partner)
 		return;
 
-	adev = &partner->adev;
+	adev = &altmode->adev;
+	partner_adev = &partner->adev;
 
 	if (is_typec_plug(adev->dev.parent)) {
 		struct typec_plug *plug = to_typec_plug(adev->dev.parent);
@@ -202,7 +204,7 @@ static void typec_altmode_put_partner(struct altmode *altmode)
 	} else {
 		partner->partner = NULL;
 	}
-	put_device(&adev->dev);
+	put_device(&partner_adev->dev);
 }
 
 static void *typec_port_match(struct device_connection *con, int ep, void *data)
@@ -465,7 +467,8 @@ static void typec_altmode_release(struct device *dev)
 {
 	struct altmode *alt = to_altmode(to_typec_altmode(dev));
 
-	typec_altmode_put_partner(alt);
+	if (!is_typec_port(dev->parent))
+		typec_altmode_put_partner(alt);
 
 	altmode_id_remove(alt->adev.dev.parent, alt->id);
 	kfree(alt);