1 files changed, 98 insertions, 36 deletions

diff --git a/drivers/comedi/drivers.c b/drivers/comedi/drivers.c
index c9ebaadc5e82..69cd2a253c66 100644
--- a/drivers/comedi/drivers.c
+++ b/drivers/comedi/drivers.c
@@ -441,6 +441,13 @@ unsigned int comedi_bytes_per_scan_cmd(struct comedi_subdevice *s,
 }
 EXPORT_SYMBOL_GPL(comedi_bytes_per_scan_cmd);
 
+static unsigned int _comedi_bytes_per_scan(struct comedi_subdevice *s)
+{
+	struct comedi_cmd *cmd = &s->async->cmd;
+
+	return comedi_bytes_per_scan_cmd(s, cmd);
+}
+
 /**
  * comedi_bytes_per_scan() - Get length of asynchronous command "scan" in bytes
  * @s: COMEDI subdevice.
@@ -458,9 +465,16 @@ EXPORT_SYMBOL_GPL(comedi_bytes_per_scan_cmd);
  */
 unsigned int comedi_bytes_per_scan(struct comedi_subdevice *s)
 {
-	struct comedi_cmd *cmd = &s->async->cmd;
+	unsigned int num_bytes;
 
-	return comedi_bytes_per_scan_cmd(s, cmd);
+	if (comedi_get_is_subdevice_running(s)) {
+		num_bytes = _comedi_bytes_per_scan(s);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		/* Use nomimal, single sample scan length. */
+		num_bytes = comedi_samples_to_bytes(s, 1);
+	}
+	return num_bytes;
 }
 EXPORT_SYMBOL_GPL(comedi_bytes_per_scan);
 
@@ -482,6 +496,17 @@ static unsigned int __comedi_nscans_left(struct comedi_subdevice *s,
 	return nscans;
 }
 
+static unsigned int _comedi_nscans_left(struct comedi_subdevice *s,
+					unsigned int nscans)
+{
+	if (nscans == 0) {
+		unsigned int nbytes = _comedi_buf_read_n_available(s);
+
+		nscans = nbytes / _comedi_bytes_per_scan(s);
+	}
+	return __comedi_nscans_left(s, nscans);
+}
+
 /**
  * comedi_nscans_left() - Return the number of scans left in the command
  * @s: COMEDI subdevice.
@@ -499,25 +524,18 @@ static unsigned int __comedi_nscans_left(struct comedi_subdevice *s,
 unsigned int comedi_nscans_left(struct comedi_subdevice *s,
 				unsigned int nscans)
 {
-	if (nscans == 0) {
-		unsigned int nbytes = comedi_buf_read_n_available(s);
-
-		nscans = nbytes / comedi_bytes_per_scan(s);
+	if (comedi_get_is_subdevice_running(s)) {
+		nscans = _comedi_nscans_left(s, nscans);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		nscans = 0;
 	}
-	return __comedi_nscans_left(s, nscans);
+	return nscans;
 }
 EXPORT_SYMBOL_GPL(comedi_nscans_left);
 
-/**
- * comedi_nsamples_left() - Return the number of samples left in the command
- * @s: COMEDI subdevice.
- * @nsamples: The expected number of samples.
- *
- * Returns the number of samples remaining to complete the command, or the
- * specified expected number of samples (@nsamples), whichever is fewer.
- */
-unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
-				  unsigned int nsamples)
+static unsigned int _comedi_nsamples_left(struct comedi_subdevice *s,
+					  unsigned int nsamples)
 {
 	struct comedi_async *async = s->async;
 	struct comedi_cmd *cmd = &async->cmd;
@@ -538,24 +556,34 @@ unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
 		return samples_left;
 	return nsamples;
 }
-EXPORT_SYMBOL_GPL(comedi_nsamples_left);
 
 /**
- * comedi_inc_scan_progress() - Update scan progress in asynchronous command
+ * comedi_nsamples_left() - Return the number of samples left in the command
  * @s: COMEDI subdevice.
- * @num_bytes: Amount of data in bytes to increment scan progress.
+ * @nsamples: The expected number of samples.
  *
- * Increments the scan progress by the number of bytes specified by @num_bytes.
- * If the scan progress reaches or exceeds the scan length in bytes, reduce
- * it modulo the scan length in bytes and set the "end of scan" asynchronous
- * event flag (%COMEDI_CB_EOS) to be processed later.
+ * Returns the number of samples remaining to complete the command, or the
+ * specified expected number of samples (@nsamples), whichever is fewer.
  */
-void comedi_inc_scan_progress(struct comedi_subdevice *s,
-			      unsigned int num_bytes)
+unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
+				  unsigned int nsamples)
+{
+	if (comedi_get_is_subdevice_running(s)) {
+		nsamples = _comedi_nsamples_left(s, nsamples);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		nsamples = 0;
+	}
+	return nsamples;
+}
+EXPORT_SYMBOL_GPL(comedi_nsamples_left);
+
+void _comedi_inc_scan_progress(struct comedi_subdevice *s,
+			       unsigned int num_bytes)
 {
 	struct comedi_async *async = s->async;
 	struct comedi_cmd *cmd = &async->cmd;
-	unsigned int scan_length = comedi_bytes_per_scan(s);
+	unsigned int scan_length = _comedi_bytes_per_scan(s);
 
 	/* track the 'cur_chan' for non-SDF_PACKED subdevices */
 	if (!(s->subdev_flags & SDF_PACKED)) {
@@ -576,8 +604,43 @@ void comedi_inc_scan_progress(struct comedi_subdevice *s,
 		async->events |= COMEDI_CB_EOS;
 	}
 }
+
+/**
+ * comedi_inc_scan_progress() - Update scan progress in asynchronous command
+ * @s: COMEDI subdevice.
+ * @num_bytes: Amount of data in bytes to increment scan progress.
+ *
+ * Increments the scan progress by the number of bytes specified by @num_bytes.
+ * If the scan progress reaches or exceeds the scan length in bytes, reduce
+ * it modulo the scan length in bytes and set the "end of scan" asynchronous
+ * event flag (%COMEDI_CB_EOS) to be processed later.
+ */
+void comedi_inc_scan_progress(struct comedi_subdevice *s,
+			      unsigned int num_bytes)
+{
+	if (comedi_get_is_subdevice_running(s)) {
+		_comedi_inc_scan_progress(s, num_bytes);
+		comedi_put_is_subdevice_running(s);
+	}
+}
 EXPORT_SYMBOL_GPL(comedi_inc_scan_progress);
 
+static unsigned int _comedi_handle_events(struct comedi_device *dev,
+					  struct comedi_subdevice *s)
+{
+	unsigned int events = s->async->events;
+
+	if (events == 0)
+		return events;
+
+	if ((events & COMEDI_CB_CANCEL_MASK) && s->cancel)
+		s->cancel(dev, s);
+
+	_comedi_event(dev, s);
+
+	return events;
+}
+
 /**
  * comedi_handle_events() - Handle events and possibly stop acquisition
  * @dev: COMEDI device.
@@ -597,16 +660,14 @@ EXPORT_SYMBOL_GPL(comedi_inc_scan_progress);
 unsigned int comedi_handle_events(struct comedi_device *dev,
 				  struct comedi_subdevice *s)
 {
-	unsigned int events = s->async->events;
-
-	if (events == 0)
-		return events;
-
-	if ((events & COMEDI_CB_CANCEL_MASK) && s->cancel)
-		s->cancel(dev, s);
-
-	comedi_event(dev, s);
+	unsigned int events;
 
+	if (comedi_get_is_subdevice_running(s)) {
+		events = _comedi_handle_events(dev, s);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		events = 0;
+	}
 	return events;
 }
 EXPORT_SYMBOL_GPL(comedi_handle_events);
@@ -677,6 +738,7 @@ static int __comedi_device_postconfig_async(struct comedi_device *dev,
 		return -ENOMEM;
 
 	init_waitqueue_head(&async->wait_head);
+	init_completion(&async->run_complete);
 	s->async = async;
 
 	async->max_bufsize = comedi_default_buf_maxsize_kb * 1024;