bcm2835-camera: Correct port_parameter_get return value

The API for port_parameter_get() requires that the
filled length is returned, or if insufficient space
that the required space is returned.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/drivers/media/platform/bcm2835/mmal-vchiq.c b/drivers/media/platform/bcm2835/mmal-vchiq.c
index e4b243b33f58913f3d2952c97d2a2e3fbbbd0ae8..ec2853ba9d4b1b0cd6e07a495a424e15159208e8 100644 (file)
--- a/drivers/media/platform/bcm2835/mmal-vchiq.c
+++ b/drivers/media/platform/bcm2835/mmal-vchiq.c
@@ -1292,6 +1292,7 @@ static int port_parameter_get(struct vchiq_mmal_instance *instance,
        struct mmal_msg m;
        struct mmal_msg *rmsg;
        VCHI_HELD_MSG_T rmsg_handle;
+       u32 reply_size;
 
        m.h.type = MMAL_MSG_TYPE_PORT_PARAMETER_GET;
 
@@ -1315,21 +1316,27 @@ static int port_parameter_get(struct vchiq_mmal_instance *instance,
        }
 
        ret = -rmsg->u.port_parameter_get_reply.status;
-       /* port_parameter_get_reply.size includes the header,
+       /*
+        * port_parameter_get_reply.size includes the header,
         * whilst *value_size doesn't.
         */
-       rmsg->u.port_parameter_get_reply.size -= (2 * sizeof(u32));
+       reply_size = rmsg->u.port_parameter_get_reply.size - (2 * sizeof(u32));
 
-       if (ret || rmsg->u.port_parameter_get_reply.size > *value_size) {
+       if (ret || (reply_size > *value_size)) {
                /* Copy only as much as we have space for
                 * but report true size of parameter
                 */
                memcpy(value, &rmsg->u.port_parameter_get_reply.value,
                       *value_size);
-               *value_size = rmsg->u.port_parameter_get_reply.size;
        } else
                memcpy(value, &rmsg->u.port_parameter_get_reply.value,
-                      rmsg->u.port_parameter_get_reply.size);
+                      reply_size);
+
+       /*
+        * Return amount of data copied if big enough,
+        * or wanted if not big enough.
+        */
+       *value_size = reply_size;
 
        pr_debug("%s:result:%d component:0x%x port:%d parameter:%d\n", __func__,
                ret, port->component->handle, port->handle, parameter_id);