[dpdk-dev] [PATCH] eal: fix rte_intr_dp_is_en() check

[Liang, Cunming]

Hi Yong,

rte_intr_dp_is_en() returns true when rte_intr_efd_enable() (the way to 
enable data-path interrupt) sets a number of event fds.
In this case, "intr_conf.rxq=1" configuration causes "nb_efd=1". The 
value comes from RTE_MIN($nb_efd, 1) from data-path, but not from link 
event.
Per link event, you shouldn't use rte_intr_dp_is_en() as the indication.
As igb_uio only has a single vector, when the conflict(both intr_rxq and 
intr_lsc turn on) happens, the intr_rxq has high priority than intr_lsc 
as default PMD behavior.
Reference as PG 3.1.9 note in 
http://dpdk.org/doc/guides/prog_guide/env_abstraction_layer.html

Regards,
Cunming

On 7/15/2016 8:36 AM, Yong Wang wrote:
> When binding a device to igb_uio with intr_conf.rxq set to 1, nb_efd
> is 1 (for link event) but rte_intr_dp_is_en() will still return true.
> rte_intr_dp_is_en() should also consider intr_handle type in addition
> to nb_efd.
>
> Signed-off-by: Yong Wang <yongwang at vmware.com>
> ---
>   lib/librte_eal/linuxapp/eal/eal_interrupts.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/lib/librte_eal/linuxapp/eal/eal_interrupts.c b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> index 47a3b20..71f63e9 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> @@ -1200,7 +1200,8 @@ rte_intr_efd_disable(struct rte_intr_handle *intr_handle)
>   int
>   rte_intr_dp_is_en(struct rte_intr_handle *intr_handle)
>   {
> -	return !(!intr_handle->nb_efd);
> +	return (!(!intr_handle->nb_efd) &&
> +		(intr_handle->type == RTE_INTR_HANDLE_VFIO_MSIX));
>   }
>   
>   int