Staging: comedi: usbdux: buffer overflow error handling

These changes guarantee that the URBs are not resubmitted in case of a
comedi buffer overflow.  Otherwise this runs in the background even when
the userspace program has terminated.

From: Bernd Porr <BerndPorr@f2s.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 18 insertions, 8 deletions

diff --git a/drivers/staging/comedi/drivers/usbdux.c b/drivers/staging/comedi/drivers/usbdux.c
index eea7dbdde0b..171a6f2ff74 100644
--- a/drivers/staging/comedi/drivers/usbdux.c
+++ b/drivers/staging/comedi/drivers/usbdux.c
@@ -509,14 +509,19 @@ static void usbduxsub_ai_IsocIrq(struct urb *urb)
         for (i = 0; i < n; i++) {
                 /* transfer data */
                 if (CR_RANGE(s->async->cmd.chanlist[i]) <= 1) {
-                        comedi_buf_put
+                        err = comedi_buf_put
                                 (s->async,
-                                le16_to_cpu(this_usbduxsub->
-                                        inBuffer[i]) ^ 0x800);
+                                 le16_to_cpu(this_usbduxsub->
+                                             inBuffer[i]) ^ 0x800);
                 } else {
-                        comedi_buf_put
+                        err = comedi_buf_put
                                 (s->async,
-                                le16_to_cpu(this_usbduxsub->inBuffer[i]));
+                                 le16_to_cpu(this_usbduxsub->inBuffer[i]));
+                }
+                if (unlikely(err == 0)) {
+                        /* buffer overflow */
+                        usbdux_ai_stop(this_usbduxsub, 0);
+                        return;
                 }
         }
         /* tell comedi that data is there */
diff --git a/drivers/staging/comedi/drivers/usbduxfast.c b/drivers/staging/comedi/drivers/usbduxfast.c
index 5862078bfbb..939b53fa569 100644
--- a/drivers/staging/comedi/drivers/usbduxfast.c
+++ b/drivers/staging/comedi/drivers/usbduxfast.c
@@ -406,7 +406,7 @@ static void usbduxfastsub_ai_Irq(struct urb *urb)
                                         udfs->ai_sample_count
                                         * sizeof(uint16_t));
                                 usbduxfast_ai_stop(udfs, 0);
-                                /* say comedi that the acquistion is over */
+                                /* tell comedi that the acquistion is over */
                                 s->async->events |= COMEDI_CB_EOA;
                                 comedi_event(udfs->comedidev, s);
                                 return;
@@ -414,8 +414,13 @@ static void usbduxfastsub_ai_Irq(struct urb *urb)
                         udfs->ai_sample_count -= n;
                 }
                 /* write the full buffer to comedi */
-                cfc_write_array_to_buffer(s, urb->transfer_buffer,
-                                          urb->actual_length);
+                err = cfc_write_array_to_buffer(s, urb->transfer_buffer,
+                                                urb->actual_length);
+                if (unlikely(err == 0)) {
+                        /* buffer overflow */
+                        usbduxfast_ai_stop(udfs, 0);
+                        return;
+                }
 
                 /* tell comedi that data is there */
                 comedi_event(udfs->comedidev, s);