[PATCH 13/14] rpmsg: Allow callback to return errors

[Bjorn Andersson]

Some rpmsg backends support holding on to and redelivering messages upon
failed handling of them, so provide a way for the callback to report and
error and allow the backends to handle this.

Signed-off-by: Bjorn Andersson <bjorn.anders...@linaro.org>
---
 drivers/rpmsg/virtio_rpmsg_bus.c | 10 ++++++----
 include/linux/rpmsg.h            |  4 ++--
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index d39e381bc596..9d681d68f7f3 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -785,8 +785,8 @@ static void rpmsg_xmit_done(struct virtqueue *svq)
 }
 
 /* invoked when a name service announcement arrives */
-static void rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
-                       void *priv, u32 src)
+static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
+                      void *priv, u32 src)
 {
        struct rpmsg_ns_msg *msg = data;
        struct rpmsg_device *newch;
@@ -802,7 +802,7 @@ static void rpmsg_ns_cb(struct rpmsg_device *rpdev, void 
*data, int len,
 
        if (len != sizeof(*msg)) {
                dev_err(dev, "malformed ns msg (%d)\n", len);
-               return;
+               return -EINVAL;
        }
 
        /*
@@ -813,7 +813,7 @@ static void rpmsg_ns_cb(struct rpmsg_device *rpdev, void 
*data, int len,
         */
        if (rpdev) {
                dev_err(dev, "anomaly: ns ept has an rpdev handle\n");
-               return;
+               return -EINVAL;
        }
 
        /* don't trust the remote processor for null terminating the name */
@@ -836,6 +836,8 @@ static void rpmsg_ns_cb(struct rpmsg_device *rpdev, void 
*data, int len,
                if (!newch)
                        dev_err(dev, "rpmsg_create_channel failed\n");
        }
+
+       return 0;
 }
 
 static int rpmsg_probe(struct virtio_device *vdev)
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index bdd1a2285733..19213e660a9b 100644
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -46,7 +46,7 @@
 struct rpmsg_device;
 struct rpmsg_endpoint;
 
-typedef void (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
+typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
 
 /**
  * struct rpmsg_channel_info - internal channel info representation
@@ -123,7 +123,7 @@ struct rpmsg_driver {
        const struct rpmsg_device_id *id_table;
        int (*probe)(struct rpmsg_device *dev);
        void (*remove)(struct rpmsg_device *dev);
-       void (*callback)(struct rpmsg_device *, void *, int, void *, u32);
+       int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
 };
 
 int register_rpmsg_device(struct rpmsg_device *dev);
-- 
2.5.0