Linux-libre 4.3.2-gnu

1 files changed, 23 insertions, 10 deletions

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index b3fda9ee4..d7e908acb 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -71,8 +71,9 @@ static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
 
 	if (avail >= to_wait) {
 		/* force a flush for non-blocking reads */
-		if (!to_wait && !avail && to_flush)
-			iio_buffer_flush_hwfifo(indio_dev, buf, to_flush);
+		if (!to_wait && avail < to_flush)
+			iio_buffer_flush_hwfifo(indio_dev, buf,
+						to_flush - avail);
 		return true;
 	}
 
@@ -90,9 +91,16 @@ static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
 
 /**
  * iio_buffer_read_first_n_outer() - chrdev read for buffer access
+ * @filp:	File structure pointer for the char device
+ * @buf:	Destination buffer for iio buffer read
+ * @n:		First n bytes to read
+ * @f_ps:	Long offset provided by the user as a seek position
  *
  * This function relies on all buffer implementations having an
  * iio_buffer as their first element.
+ *
+ * Return: negative values corresponding to error codes or ret != 0
+ *	   for ending the reading activity
  **/
 ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
 				      size_t n, loff_t *f_ps)
@@ -100,8 +108,7 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
 	struct iio_dev *indio_dev = filp->private_data;
 	struct iio_buffer *rb = indio_dev->buffer;
 	size_t datum_size;
-	size_t to_wait = 0;
-	size_t to_read;
+	size_t to_wait;
 	int ret;
 
 	if (!indio_dev->info)
@@ -119,14 +126,14 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
 	if (!datum_size)
 		return 0;
 
-	to_read = min_t(size_t, n / datum_size, rb->watermark);
-
-	if (!(filp->f_flags & O_NONBLOCK))
-		to_wait = to_read;
+	if (filp->f_flags & O_NONBLOCK)
+		to_wait = 0;
+	else
+		to_wait = min_t(size_t, n / datum_size, rb->watermark);
 
 	do {
 		ret = wait_event_interruptible(rb->pollq,
-			iio_buffer_ready(indio_dev, rb, to_wait, to_read));
+		      iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size));
 		if (ret)
 			return ret;
 
@@ -143,6 +150,12 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
 
 /**
  * iio_buffer_poll() - poll the buffer to find out if it has data
+ * @filp:	File structure pointer for device access
+ * @wait:	Poll table structure pointer for which the driver adds
+ *		a wait queue
+ *
+ * Return: (POLLIN | POLLRDNORM) if data is available for reading
+ *	   or 0 for other cases
  */
 unsigned int iio_buffer_poll(struct file *filp,
 			     struct poll_table_struct *wait)
@@ -1136,7 +1149,7 @@ int iio_scan_mask_query(struct iio_dev *indio_dev,
 EXPORT_SYMBOL_GPL(iio_scan_mask_query);
 
 /**
- * struct iio_demux_table() - table describing demux memcpy ops
+ * struct iio_demux_table - table describing demux memcpy ops
  * @from:	index to copy from
  * @to:		index to copy to
  * @length:	how many bytes to copy