On 3/17/21 6:40 AM, Cheng Jiang wrote:
> We use ioat ring space for determining if ioat callbacks can enqueue a
> packet to ioat device. But there is one slot can't be used in ioat
> ring due to the ioat driver design, so we need to reduce one slot in
> ioat ring to prevent ring size mismatch in ioat callbacks.
>
> Fixes: 2aa47e94bfb2 ("examples/vhost: add ioat ring space count and check")
> Cc: sta...@dpdk.org
>
> Signed-off-by: Cheng Jiang <cheng1.ji...@intel.com>
> ---
> examples/vhost/ioat.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/examples/vhost/ioat.c b/examples/vhost/ioat.c
> index 60b73be93..9cb5e0d50 100644
> --- a/examples/vhost/ioat.c
> +++ b/examples/vhost/ioat.c
> @@ -113,7 +113,7 @@ open_ioat(const char *value)
> goto out;
> }
> rte_rawdev_start(dev_id);
> - cb_tracker[dev_id].ioat_space = IOAT_RING_SIZE;
> + cb_tracker[dev_id].ioat_space = IOAT_RING_SIZE - 1;
That really comforts me in thinking we need a generic abstraction for
DMA devices. How is the application developer supposed to know that
the DMA driver has such weird limitations?
Can the driver be fixed to have a proper behavior?
> dma_info->nr++;
> i++;
> }
>
