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>

diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
index 048381c..261131c 100644 (file)
--- 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;
 }

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 8a35144..e680fcf 100644 (file)
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -898,12 +898,15 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
        con->num = index + 1;
        con->ucsi = ucsi;
 
+       /* Delay other interactions with the con until registration is complete */
+       mutex_lock(&con->lock);
+
        /* Get connector capability */
        command = UCSI_GET_CONNECTOR_CAPABILITY;
        command |= UCSI_CONNECTOR_NUMBER(con->num);
        ret = ucsi_send_command(ucsi, command, &con->cap, sizeof(con->cap));
        if (ret < 0)
-               return ret;
+               goto out;
 
        if (con->cap.op_mode & UCSI_CONCAP_OPMODE_DRP)
                cap->data = TYPEC_PORT_DRD;
@@ -935,26 +938,32 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
 
        ret = ucsi_register_port_psy(con);
        if (ret)
-               return ret;
+               goto out;
 
        /* Register the connector */
        con->port = typec_register_port(ucsi->dev, cap);
-       if (IS_ERR(con->port))
-               return PTR_ERR(con->port);
+       if (IS_ERR(con->port)) {
+               ret = PTR_ERR(con->port);
+               goto out;
+       }
 
        /* Alternate modes */
        ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_CON);
-       if (ret)
+       if (ret) {
                dev_err(ucsi->dev, "con%d: failed to register alt modes\n",
                        con->num);
+               goto out;
+       }
 
        /* Get the status */
        command = UCSI_GET_CONNECTOR_STATUS | UCSI_CONNECTOR_NUMBER(con->num);
        ret = ucsi_send_command(ucsi, command, &con->status, sizeof(con->status));
        if (ret < 0) {
                dev_err(ucsi->dev, "con%d: failed to get status\n", con->num);
-               return 0;
+               ret = 0;
+               goto out;
        }
+       ret = 0; /* ucsi_send_command() returns length on success */
 
        switch (UCSI_CONSTAT_PARTNER_TYPE(con->status.flags)) {
        case UCSI_CONSTAT_PARTNER_TYPE_UFP:
@@ -979,17 +988,21 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
 
        if (con->partner) {
                ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_SOP);
-               if (ret)
+               if (ret) {
                        dev_err(ucsi->dev,
                                "con%d: failed to register alternate modes\n",
                                con->num);
-               else
+                       ret = 0;
+               } else {
                        ucsi_altmode_update_active(con);
+               }
        }
 
        trace_ucsi_register_port(con->num, &con->status);
 
-       return 0;
+out:
+       mutex_unlock(&con->lock);
+       return ret;
 }
 
 /**