Re: [PATCH 08/13] swiotlb-xen: always use dma-direct helpers to alloc coherent pages

Boris Ostrovsky
2019-09-03T22:26:05Z

(Now with correct address for Juergen)

On 9/3/19 6:15 PM, Boris Ostrovsky wrote:
> On 9/2/19 9:03 AM, Christoph Hellwig wrote:
>> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
>> index b8808677ae1d..f9dd4cb6e4b3 100644
>> --- a/drivers/xen/swiotlb-xen.c
>> +++ b/drivers/xen/swiotlb-xen.c
>> @@ -299,8 +299,7 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
>> * address. In fact on ARM virt_to_phys only works for kernel direct
>> * mapped RAM memory. Also see comment below.
>> */
>> - ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
>> -
>> + ret = dma_direct_alloc(hwdev, size, dma_handle, flags, attrs);
>
> If I am reading __dma_direct_alloc_pages() correctly there is a path
> that will force us to use GFP_DMA32 and as Juergen pointed out in
> another message that may not be desirable.
>
> -boris
>
>
>