On Friday, May 10, 2013 6:07 AM, Ian Abbott wrote:
> 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@xxxxxxxxx>
> ---
> drivers/staging/comedi/comedi_buf.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c
> index b6cd67a..d4be0e6 100644
> --- a/drivers/staging/comedi/comedi_buf.c
> +++ b/drivers/staging/comedi/comedi_buf.c
> @@ -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);
Would it be better to put this test in comedi_buf_alloc() and return a different
errno?
With the check in __comedi_buf_alloc(), comedi_buf_alloc() needlessly calls
__comedi_buf_free() and __comedi_buf_alloc() before returning an errno of
-ENOMEM. I think an errno of -ENOSYS, or even -EINVAL, would be more
appropriate.
Regards,
Hartley
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