[PATCH 1/5] iommu: Replace uses of IOMMU_CAP_CACHE_COHERENCY with dev_is_dma_coherent()

[Christoph Hellwig]

On Tue, Apr 05, 2022 at 01:16:00PM -0300, Jason Gunthorpe wrote:
> diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c
> index 760b254ba42d6b..24d118198ac756 100644
> --- a/drivers/infiniband/hw/usnic/usnic_uiom.c
> +++ b/drivers/infiniband/hw/usnic/usnic_uiom.c
> @@ -42,6 +42,7 @@
>  #include <linux/list.h>
>  #include <linux/pci.h>
>  #include <rdma/ib_verbs.h>
> +#include <linux/dma-map-ops.h>
>  
>  #include "usnic_log.h"
>  #include "usnic_uiom.h"
> @@ -474,6 +475,12 @@ int usnic_uiom_attach_dev_to_pd(struct usnic_uiom_pd *pd, struct device *dev)
>  	struct usnic_uiom_dev *uiom_dev;
>  	int err;
>  
> +	if (!dev_is_dma_coherent(dev)) {

Which part of the comment at the top of dma-map-ops.h is not clear
enough to you?