On Tue, Jun 25, 2019 at 12:26:59PM +0100, Ian Abbott wrote:
> drivers/staging/comedi/comedi_buf.c | 150 ++++++++++++++++++---------
> drivers/staging/comedi/comedi_fops.c | 39 ++++---
> 2 files changed, 125 insertions(+), 64 deletions(-)
>
> diff --git a/drivers/staging/comedi/comedi_buf.c
> b/drivers/staging/comedi/comedi_buf.c
> index d2c8cc72a99d..3ef3ddabf139 100644
> --- a/drivers/staging/comedi/comedi_buf.c
> +++ b/drivers/staging/comedi/comedi_buf.c
> @@ -27,18 +27,19 @@ static void comedi_buf_map_kref_release(struct kref *kref)
> unsigned int i;
>
> if (bm->page_list) {
> - for (i = 0; i < bm->n_pages; i++) {
> - buf = &bm->page_list[i];
> - clear_bit(PG_reserved,
> - &(virt_to_page(buf->virt_addr)->flags));
> - if (bm->dma_dir != DMA_NONE) {
> -#ifdef CONFIG_HAS_DMA
> - dma_free_coherent(bm->dma_hw_dev,
> - PAGE_SIZE,
> - buf->virt_addr,
> - buf->dma_addr);
> -#endif
> - } else {
> + if (bm->dma_dir != DMA_NONE) {
> + /*
> + * DMA buffer was allocated as a single block.
> + * Address is in page_list[0].
> + */
> + buf = &bm->page_list[0];
> + dma_free_coherent(bm->dma_hw_dev,
> + PAGE_SIZE * bm->n_pages,
> + buf->virt_addr, buf->dma_addr);
> + } else {
> + for (i = 0; i < bm->n_pages; i++) {
> + buf = &bm->page_list[i];
> + ClearPageReserved(virt_to_page(buf->virt_addr));
I think we need a NULL check here:
if (!buf->virt_addr)
continue;
> free_page((unsigned long)buf->virt_addr);
> }
> }
> @@ -57,7 +58,8 @@ static void __comedi_buf_free(struct comedi_device *dev,
regards,
dan carpenter
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