Re: [dpdk-dev] [PATCH] eal: Fixes VFIO/sysfs race condition

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 31-Mar-20 5:56 PM, Michael Haeuptle wrote:
> This fix treats a 0 return value from vfio_open_group_fd
> in vfio_get_group_fd as the intended error condition instead
> of putting an incorrect 0 file descriptor in the vfio_group table.
> 
> Sometimes, the creation of device files in sysfs is not
> instantaneously causing vfio_open_groupfd to return 0.
> This has been observed when hot removing/adding multiple
> NVMe devices (>=4).
> 
> Signed-off-by: Michael Haeuptle <michael.haeuptle@hpe.com>
> ---
>   lib/librte_eal/linux/eal_vfio.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/librte_eal/linux/eal_vfio.c b/lib/librte_eal/linux/eal_vfio.c
> index 4502aefed..1979f6fdd 100644
> --- a/lib/librte_eal/linux/eal_vfio.c
> +++ b/lib/librte_eal/linux/eal_vfio.c
> @@ -379,7 +379,7 @@ vfio_get_group_fd(struct vfio_config *vfio_cfg,
>   	}
>   
>   	vfio_group_fd = vfio_open_group_fd(iommu_group_num);
> -	if (vfio_group_fd < 0) {
> +	if (vfio_group_fd <= 0) {
>   		RTE_LOG(ERR, EAL, "Failed to open group %d\n", iommu_group_num);
>   		return -1;
>   	}
> 

If it's returning an invalid value, is that a kernel bug?

I mean, looks fine to me, so

Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

-- 
Thanks,
Anatoly