staging: comedi: complain if dma buffer allocation not supported

When allocating a buffer to support asynchronous comedi commands, if a
DMA coherent buffer was requested but `CONFIG_HAS_DMA` is undefined,
bail out of local helper function `__comedi_buf_alloc()` with an error
message.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott 2013-05-10 14:07:16 +01:00 committed by Greg Kroah-Hartman
parent bd304a736a
commit e9166139f6

View File

@ -76,6 +76,12 @@ static void __comedi_buf_alloc(struct comedi_device *dev,
struct comedi_buf_page *buf;
unsigned i;
if (!IS_ENABLED(CONFIG_HAS_DMA) && s->async_dma_dir != DMA_NONE) {
dev_err(dev->class_dev,
"dma buffer allocation not supported\n");
return;
}
async->buf_page_list = vzalloc(sizeof(*buf) * n_pages);
if (async->buf_page_list)
pages = vmalloc(sizeof(struct page *) * n_pages);