usb: typec: ucsi: Hold con->lock for the entire duration of ucsi_register_port()

Commit 081da1325d35 ("usb: typec: ucsi: displayport: Fix a potential race
during registration") made the ucsi code hold con->lock in
ucsi_register_displayport(). But we really don't want any interactions
with the connector to run before the port-registration process is fully
complete.

This commit moves the taking of con->lock from ucsi_register_displayport()
into ucsi_register_port() to achieve this.

Cc: stable@vger.kernel.org
Fixes: 081da1325d35 ("usb: typec: ucsi: displayport: Fix a potential race during registration")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200809141904.4317-5-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 8 deletions

diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
index 048381c058a5..261131c9e37c 100644
--- a/drivers/usb/typec/ucsi/displayport.c
+++ b/drivers/usb/typec/ucsi/displayport.c
@@ -288,8 +288,6 @@ struct typec_altmode *ucsi_register_displayport(struct ucsi_connector *con,
 	struct typec_altmode *alt;
 	struct ucsi_dp *dp;
 
-	mutex_lock(&con->lock);
-
 	/* We can't rely on the firmware with the capabilities. */
 	desc->vdo |= DP_CAP_DP_SIGNALING | DP_CAP_RECEPTACLE;
 
@@ -298,15 +296,12 @@ struct typec_altmode *ucsi_register_displayport(struct ucsi_connector *con,
 	desc->vdo |= all_assignments << 16;
 
 	alt = typec_port_register_altmode(con->port, desc);
-	if (IS_ERR(alt)) {
-		mutex_unlock(&con->lock);
+	if (IS_ERR(alt))
 		return alt;
-	}
 
 	dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL);
 	if (!dp) {
 		typec_unregister_altmode(alt);
-		mutex_unlock(&con->lock);
 		return ERR_PTR(-ENOMEM);
 	}
 
@@ -319,7 +314,5 @@ struct typec_altmode *ucsi_register_displayport(struct ucsi_connector *con,
 	alt->ops = &ucsi_displayport_ops;
 	typec_altmode_set_drvdata(alt, dp);
 
-	mutex_unlock(&con->lock);
-
 	return alt;
 }