Re: [PATCH v1 05/16] vfio/ccw: replace copy_from_iova with vfio_dma_rw

Jason Gunthorpe
2022-11-22T01:41:16Z

On Mon, Nov 21, 2022 at 10:40:45PM +0100, Eric Farman wrote:
> It was suggested [1] that we replace the old copy_from_iova() routine
> (which pins a page, does a memcpy, and unpins the page) with the
> newer vfio_dma_rw() interface.
>
> This has a modest improvement in the overall time spent through the
> fsm_io_request() path, and simplifies some of the code to boot.
>
> [1] https://lore.kernel.org/r/20220706170553.GK693670@nvidia.com/
>
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Eric Farman <farman@linux.ibm.com>
> ---
> drivers/s390/cio/vfio_ccw_cp.c | 56 +++-------------------------------
> 1 file changed, 5 insertions(+), 51 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason