platform/chrome: Fix locking pattern in wilco_ec_mailbox()

Before, ec->data_buffer could be written to from multiple
contexts at the same time. Since the ec is shared data,
it needs to be inside the mutex as well.

Fixes: 7b3d4f44abf0 ("platform/chrome: Add new driver for Wilco EC")
Signed-off-by: Nick Crews <ncrews@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Benson Leung <bleung@chromium.org>

diff --git a/drivers/platform/chrome/wilco_ec/mailbox.c b/drivers/platform/chrome/wilco_ec/mailbox.c
index f6ff29a..1435566 100644 (file)
--- a/drivers/platform/chrome/wilco_ec/mailbox.c
+++ b/drivers/platform/chrome/wilco_ec/mailbox.c
@@ -223,11 +223,11 @@ int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg)
                msg->command, msg->type, msg->flags, msg->response_size,
                msg->request_size);
 
+       mutex_lock(&ec->mailbox_lock);
        /* Prepare request packet */
        rq = ec->data_buffer;
        wilco_ec_prepare(msg, rq);
 
-       mutex_lock(&ec->mailbox_lock);
        ret = wilco_ec_transfer(ec, msg, rq);
        mutex_unlock(&ec->mailbox_lock);