add an API to check if a streamming mapping needs sync calls

[Christoph Hellwig <hch@xxxxxx>]

Hi all,

this series lifts the somewhat hacky checks in the XSK code if a DMA
streaming mapping needs dma_sync_single_for_{device,cpu} calls to the
DMA API.


Diffstat:
 Documentation/core-api/dma-api.rst |    8 +++++
 include/linux/dma-direct.h         |    1 
 include/linux/dma-mapping.h        |    5 +++
 include/net/xsk_buff_pool.h        |    6 ++--
 kernel/dma/direct.c                |    6 ++++
 kernel/dma/mapping.c               |   10 ++++++
 net/xdp/xsk_buff_pool.c            |   54 ++-----------------------------------
 7 files changed, 37 insertions(+), 53 deletions(-)