staging:iio: pull out demux cleanup for a particular buffer.

This will come in handy again when we move to multiple buffers
so lets pull it out into a little utility function now.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Acked-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/iio/industrialio-buffer.c

@@ -655,19 +655,25 @@ int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data,
 }
 EXPORT_SYMBOL_GPL(iio_push_to_buffer);
 
+static void iio_buffer_demux_free(struct iio_buffer *buffer)
+{
+	struct iio_demux_table *p, *q;
+	list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
+		list_del(&p->l);
+		kfree(p);
+	}
+}
+
 int iio_update_demux(struct iio_dev *indio_dev)
 {
 	const struct iio_chan_spec *ch;
 	struct iio_buffer *buffer = indio_dev->buffer;
 	int ret, in_ind = -1, out_ind, length;
 	unsigned in_loc = 0, out_loc = 0;
-	struct iio_demux_table *p, *q;
+	struct iio_demux_table *p;
 
 	/* Clear out any old demux */
-	list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
-		list_del(&p->l);
-		kfree(p);
-	}
+	iio_buffer_demux_free(buffer);
 	kfree(buffer->demux_bounce);
 	buffer->demux_bounce = NULL;
 
@@ -742,10 +748,8 @@ int iio_update_demux(struct iio_dev *indio_dev)
 	return 0;
 
 error_clear_mux_table:
-	list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
-		list_del(&p->l);
-		kfree(p);
-	}
+	iio_buffer_demux_free(buffer);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(iio_update_demux);