iio: buffer: hw-consumer: remove redundant scan_mask flexible array

The scan_mask flexible array member in hw_consumer_buffer duplicates
the scan_mask pointer already present in struct iio_buffer. Remove it
and allocate the bitmap directly with bitmap_zalloc(), assigning it to
buf->buffer.scan_mask. This simplifies the code and there's no need for
the flex array allocation.

Signed-off-by: Nuno Sá <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Jonathan Cameron <[email protected]>

drivers/iio/buffer/industrialio-hw-consumer.c

@@ -28,7 +28,6 @@ struct hw_consumer_buffer {
 	struct list_head head;
 	struct iio_dev *indio_dev;
 	struct iio_buffer buffer;
-	long scan_mask[];
 };
 
 static struct hw_consumer_buffer *iio_buffer_to_hw_consumer_buffer(
@@ -52,7 +51,6 @@ static const struct iio_buffer_access_funcs iio_hw_buf_access = {
 static struct hw_consumer_buffer *iio_hw_consumer_get_buffer(
 	struct iio_hw_consumer *hwc, struct iio_dev *indio_dev)
 {
-	unsigned int mask_longs = BITS_TO_LONGS(iio_get_masklength(indio_dev));
 	struct hw_consumer_buffer *buf;
 
 	list_for_each_entry(buf, &hwc->buffers, head) {
@@ -60,13 +58,18 @@ static struct hw_consumer_buffer *iio_hw_consumer_get_buffer(
 			return buf;
 	}
 
-	buf = kzalloc_flex(*buf, scan_mask, mask_longs);
+	buf = kzalloc_obj(*buf);
 	if (!buf)
 		return NULL;
 
 	buf->buffer.access = &iio_hw_buf_access;
 	buf->indio_dev = indio_dev;
-	buf->buffer.scan_mask = buf->scan_mask;
+	buf->buffer.scan_mask = bitmap_zalloc(iio_get_masklength(indio_dev),
+					      GFP_KERNEL);
+	if (!buf->buffer.scan_mask) {
+		kfree(buf);
+		return NULL;
+	}
 
 	iio_buffer_init(&buf->buffer);
 	list_add_tail(&buf->head, &hwc->buffers);