staging: comedi: usbduxsigma: introduce usbduxsigma_ao_handle_urb()

Factor the urb handling and resubmit out of the analog output urb
completion handler and tidy it up. This allows a common exit path
to be used in the completion handler to stop the async command and
handle the events.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: Bernd Porr <mail@berndporr.me.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
index a869e38..985c6f0 100644 (file)
--- a/drivers/staging/comedi/drivers/usbduxsigma.c
+++ b/drivers/staging/comedi/drivers/usbduxsigma.c
@@ -349,62 +349,25 @@ static int usbduxsigma_ao_cancel(struct comedi_device *dev,
        return 0;
 }
 
-static void usbduxsigma_ao_urb_complete(struct urb *urb)
+static void usbduxsigma_ao_handle_urb(struct comedi_device *dev,
+                                     struct comedi_subdevice *s,
+                                     struct urb *urb)
 {
-       struct comedi_device *dev = urb->context;
        struct usbduxsigma_private *devpriv = dev->private;
-       struct comedi_subdevice *s = dev->write_subdev;
-       struct comedi_cmd *cmd = &s->async->cmd;
+       struct comedi_async *async = s->async;
+       struct comedi_cmd *cmd = &async->cmd;
        uint8_t *datap;
        int ret;
        int i;
 
-       switch (urb->status) {
-       case 0:
-               /* success */
-               break;
-
-       case -ECONNRESET:
-       case -ENOENT:
-       case -ESHUTDOWN:
-       case -ECONNABORTED:
-               /* happens after an unlink command */
-               if (devpriv->ao_cmd_running) {
-                       usbduxsigma_ao_stop(dev, 0);    /* w/o unlink */
-                       s->async->events |= COMEDI_CB_EOA;
-                       comedi_event(dev, s);
-               }
-               return;
-
-       default:
-               /* a real error */
-               if (devpriv->ao_cmd_running) {
-                       dev_err(dev->class_dev,
-                               "%s: non-zero urb status (%d)\n",
-                               __func__, urb->status);
-                       usbduxsigma_ao_stop(dev, 0);    /* w/o unlink */
-                       s->async->events |= (COMEDI_CB_ERROR | COMEDI_CB_EOA);
-                       comedi_event(dev, s);
-               }
-               return;
-       }
-
-       if (!devpriv->ao_cmd_running)
-               return;
-
        devpriv->ao_counter--;
-       if ((int)devpriv->ao_counter <= 0) {
-               /* timer zero, transfer from comedi */
+       if (devpriv->ao_counter == 0) {
                devpriv->ao_counter = devpriv->ao_timer;
 
                if (cmd->stop_src == TRIG_COUNT) {
-                       /* not continuous, fixed number of samples */
                        devpriv->ao_sample_count--;
                        if (devpriv->ao_sample_count < 0) {
-                               usbduxsigma_ao_stop(dev, 0);    /* w/o unlink */
-                               /* acquistion is over, tell comedi */
-                               s->async->events |= COMEDI_CB_EOA;
-                               comedi_event(dev, s);
+                               async->events |= COMEDI_CB_EOA;
                                return;
                        }
                }
@@ -416,44 +379,85 @@ static void usbduxsigma_ao_urb_complete(struct urb *urb)
                        unsigned int chan = CR_CHAN(cmd->chanlist[i]);
                        unsigned short val;
 
-                       ret = comedi_buf_get(s, &val);
-                       if (ret < 0) {
+                       if (!comedi_buf_get(s, &val)) {
                                dev_err(dev->class_dev, "buffer underflow\n");
-                               s->async->events |= (COMEDI_CB_EOA |
-                                                    COMEDI_CB_OVERFLOW);
+                               async->events |= COMEDI_CB_OVERFLOW;
+                               return;
                        }
+
                        *datap++ = val;
                        *datap++ = chan;
                        s->readback[chan] = val;
-
-                       s->async->events |= COMEDI_CB_BLOCK;
-                       comedi_event(dev, s);
                }
+               async->events |= COMEDI_CB_BLOCK;
        }
 
-       urb->transfer_buffer_length = SIZEOUTBUF;
-       urb->dev = comedi_to_usb_dev(dev);
-       urb->status = 0;
-       if (devpriv->high_speed)
-               urb->interval = 8;      /* uframes */
-       else
-               urb->interval = 1;      /* frames */
-       urb->number_of_packets = 1;
-       urb->iso_frame_desc[0].offset = 0;
-       urb->iso_frame_desc[0].length = SIZEOUTBUF;
-       urb->iso_frame_desc[0].status = 0;
-       ret = usb_submit_urb(urb, GFP_ATOMIC);
-       if (ret < 0) {
-               dev_err(dev->class_dev,
-                       "%s: urb resubmit failed (%d)\n",
-                       __func__, ret);
-               if (ret == -EL2NSYNC)
+       /* if command is still running, resubmit urb */
+       if (!(async->events & COMEDI_CB_CANCEL_MASK)) {
+               urb->transfer_buffer_length = SIZEOUTBUF;
+               urb->dev = comedi_to_usb_dev(dev);
+               urb->status = 0;
+               if (devpriv->high_speed)
+                       urb->interval = 8;      /* uframes */
+               else
+                       urb->interval = 1;      /* frames */
+               urb->number_of_packets = 1;
+               urb->iso_frame_desc[0].offset = 0;
+               urb->iso_frame_desc[0].length = SIZEOUTBUF;
+               urb->iso_frame_desc[0].status = 0;
+               ret = usb_submit_urb(urb, GFP_ATOMIC);
+               if (ret < 0) {
                        dev_err(dev->class_dev,
-                               "buggy USB host controller or bug in IRQ handler\n");
-               usbduxsigma_ao_stop(dev, 0);    /* w/o unlink */
-               s->async->events |= (COMEDI_CB_EOA | COMEDI_CB_ERROR);
-               comedi_event(dev, s);
+                               "%s: urb resubmit failed (%d)\n",
+                               __func__, ret);
+                       if (ret == -EL2NSYNC)
+                               dev_err(dev->class_dev,
+                                       "buggy USB host controller or bug in IRQ handler\n");
+                       async->events |= COMEDI_CB_ERROR;
+               }
+       }
+}
+
+static void usbduxsigma_ao_urb_complete(struct urb *urb)
+{
+       struct comedi_device *dev = urb->context;
+       struct usbduxsigma_private *devpriv = dev->private;
+       struct comedi_subdevice *s = dev->write_subdev;
+       struct comedi_async *async = s->async;
+
+       /* exit if not running a command, do not resubmit urb */
+       if (!devpriv->ao_cmd_running)
+               return;
+
+       switch (urb->status) {
+       case 0:
+               usbduxsigma_ao_handle_urb(dev, s, urb);
+               break;
+
+       case -ECONNRESET:
+       case -ENOENT:
+       case -ESHUTDOWN:
+       case -ECONNABORTED:
+               /* happens after an unlink command */
+               async->events |= COMEDI_CB_ERROR;
+               break;
+
+       default:
+               /* a real error */
+               dev_err(dev->class_dev, "%s: non-zero urb status (%d)\n",
+                       __func__, urb->status);
+               async->events |= COMEDI_CB_ERROR;
+               break;
        }
+
+       /*
+        * comedi_handle_events() cannot be used in this driver. The (*cancel)
+        * operation would unlink the urb.
+        */
+       if (async->events & COMEDI_CB_CANCEL_MASK)
+               usbduxsigma_ao_stop(dev, 0);
+
+       comedi_event(dev, s);
 }
 
 static int usbduxsigma_submit_urbs(struct comedi_device *dev,