greybus: update gbuf status for completion handlers

Currently, if a USB urb completes with an error, that error status
is not transferred back to the gbuf that it's associated with.  For
inbound data there's not a lot we can do about an error, but for
outbound data, this means there is no notification to the submitter
that something went wrong.

For outbound data copy the urb status directly back to the gbuf as
its status.  Follow USB's lead and set the status to -EINPROGRESS
while a gbuf is "in flight."  Assign a gbuf an initial status value
of -EBADR to help identify use of never-set status values.

When an inbound urb fails (SVC or CPort), currently the urb is just
leaked, more or less (i.e., we lose an urb posted to receive
incoming data).  Change that so such an error is reported, but
then re-submitted.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/es1-ap-usb.c

@@ -274,10 +274,11 @@ static void svc_in_callback(struct urb *urb)
 	int status = check_urb_status(urb);
 	int retval;
 
-	if (status == -EAGAIN)
+	if (status) {
+		if (status != -EAGAIN)
+			dev_err(dev, "urb svc in error %d (dropped)\n", status);
 		goto exit;
-	if (status)
-		return;
+	}
 
 	/* We have a message, create a new message structure, add it to the
 	 * list, and wake up our thread that will process the messages.
@@ -300,10 +301,12 @@ static void cport_in_callback(struct urb *urb)
 	u8 cport;
 	u8 *data;
 
-	if (status == -EAGAIN)
+	if (status) {
+		if (status != -EAGAIN)
+			dev_err(dev, "urb cport in error %d (dropped)\n",
+				status);
 		goto exit;
-	if (status)
-		return;
+	}
 
 	/* The size has to be at least one, for the cport id */
 	if (!urb->actual_length) {
@@ -337,6 +340,9 @@ static void cport_out_callback(struct urb *urb)
 	unsigned long flags;
 	int i;
 
+	/* Record whether the transfer was successful */
+	gbuf->status = check_urb_status(urb);
+
 	/*
 	 * See if this was an urb in our pool, if so mark it "free", otherwise
 	 * we need to free it ourselves.

drivers/staging/greybus/gbuf.c

@@ -54,6 +54,7 @@ struct gbuf *greybus_alloc_gbuf(struct gb_connection *connection,
 	gbuf->outbound = outbound;
 	gbuf->complete = complete;
 	gbuf->context = context;
+	gbuf->status = -EBADR;	/* Initial value--means "never set" */
 
 	/* Host controller specific allocation for the actual buffer */
 	retval = connection->hd->driver->alloc_gbuf_data(gbuf, size, gfp_mask);
@@ -98,6 +99,8 @@ int greybus_submit_gbuf(struct gbuf *gbuf, gfp_t gfp_mask)
 {
 	struct greybus_host_device *hd = gbuf->connection->hd;
 
+	gbuf->status = -EINPROGRESS;
+
 	return hd->driver->submit_gbuf(gbuf, gfp_mask);
 }
 

drivers/staging/greybus/operation.c

@@ -424,6 +424,7 @@ void gb_connection_operation_recv(struct gb_connection *connection,
 		}
 		gb_operation_remove(operation);
 		gbuf = operation->response;
+		gbuf->status = GB_OP_SUCCESS;	/* If we got here we're good */
 		if (size > gbuf->transfer_buffer_length) {
 			gb_connection_err(connection, "recv buffer too small");
 			return;