greybus: encapsulate URB status checking

Define a new common function check_urb_status() that looks at the
status in a completed URB (containing incoming data) and issues
warnings in a consistent way.  It returns -EAGAIN to signal an
unrecognized status was seen, so the caller can ignore it and
re-post the URB to receive the next incoming data.  This
consolidates three blocks of code into one.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

diff --git a/drivers/staging/greybus/es1-ap-usb.c b/drivers/staging/greybus/es1-ap-usb.c
index dfe96cb..7ce3a77 100644 (file)
--- a/drivers/staging/greybus/es1-ap-usb.c
+++ b/drivers/staging/greybus/es1-ap-usb.c
@@ -227,17 +227,16 @@ static struct greybus_host_driver es1_driver = {
        .submit_gbuf            = submit_gbuf,
 };
 
-/* Callback for when we get a SVC message */
-static void svc_callback(struct urb *urb)
+/* Common function to report consistent warnings based on URB status */
+static int check_urb_status(struct urb *urb)
 {
-       struct es1_ap_dev *es1 = urb->context;
        struct device *dev = &urb->dev->dev;
        int status = urb->status;
-       int retval;
 
        switch (status) {
        case 0:
-               break;
+               return 0;
+
        case -EOVERFLOW:
                dev_err(dev, "%s: overflow actual length is %d\n",
                        __func__, urb->actual_length);
@@ -246,11 +245,25 @@ static void svc_callback(struct urb *urb)
        case -ESHUTDOWN:
        case -EILSEQ:
                /* device is gone, stop sending */
-               return;
-       default:
-               dev_err(dev, "%s: unknown status %d\n", __func__, status);
-               goto exit;
+               return status;
        }
+       dev_err(dev, "%s: unknown status %d\n", __func__, status);
+
+       return -EAGAIN;
+}
+
+/* Callback for when we get a SVC message */
+static void svc_in_callback(struct urb *urb)
+{
+       struct es1_ap_dev *es1 = urb->context;
+       struct device *dev = &urb->dev->dev;
+       int status = check_urb_status(urb);
+       int retval;
+
+       if (status == -EAGAIN)
+               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.
@@ -268,27 +281,15 @@ static void cport_in_callback(struct urb *urb)
 {
        struct device *dev = &urb->dev->dev;
        struct es1_ap_dev *es1 = urb->context;
-       int status = urb->status;
+       int status = check_urb_status(urb);
        int retval;
        u8 cport;
        u8 *data;
 
-       switch (status) {
-       case 0:
-               break;
-       case -EOVERFLOW:
-               dev_err(dev, "%s: overflow actual length is %d\n",
-                       __func__, urb->actual_length);
-       case -ECONNRESET:
-       case -ENOENT:
-       case -ESHUTDOWN:
-       case -EILSEQ:
-               /* device is gone, stop sending */
-               return;
-       default:
-               dev_err(dev, "%s: unknown status %d\n", __func__, status);
+       if (status == -EAGAIN)
                goto exit;
-       }
+       if (status)
+               return;
 
        /* The size has to be more then just an "empty" transfer */
        if (urb->actual_length <= 2) {
@@ -318,35 +319,15 @@ exit:
 
 static void cport_out_callback(struct urb *urb)
 {
-       struct device *dev = &urb->dev->dev;
        struct gbuf *gbuf = urb->context;
        struct es1_ap_dev *es1 = gbuf->hdpriv;
        unsigned long flags;
-       int status = urb->status;
        int i;
 
-       /* do we care about errors going back up? */
-       switch (status) {
-       case 0:
-               break;
-       case -EOVERFLOW:
-               dev_err(dev, "%s: overflow actual length is %d\n",
-                       __func__, urb->actual_length);
-       case -ECONNRESET:
-       case -ENOENT:
-       case -ESHUTDOWN:
-       case -EILSEQ:
-               /* device is gone, stop sending */
-               goto exit;
-       default:
-               dev_err(dev, "%s: unknown status %d\n", __func__, status);
-               goto exit;
-       }
-
-       /* Tell the core the gbuf is properly sent */
-       greybus_gbuf_finished(gbuf);
+       /* If no error, tell the core the gbuf is properly sent */
+       if (!check_urb_status(urb))
+               greybus_gbuf_finished(gbuf);
 
-exit:
        /*
         * See if this was an urb in our pool, if so mark it "free", otherwise
         * we need to free it ourselves.
@@ -443,7 +424,7 @@ static int ap_probe(struct usb_interface *interface,
 
        usb_fill_int_urb(es1->svc_urb, udev,
                         usb_rcvintpipe(udev, es1->svc_endpoint),
-                        es1->svc_buffer, ES1_SVC_MSG_SIZE, svc_callback,
+                        es1->svc_buffer, ES1_SVC_MSG_SIZE, svc_in_callback,
                         es1, svc_interval);
        retval = usb_submit_urb(es1->svc_urb, GFP_KERNEL);
        if (retval)