On Wed, Apr 29, 2020 at 04:23:04PM +0200, Arnd Bergmann wrote:
> During randconfig build testing, I ran into a configuration that has
> CONFIG_VHOST=m, CONFIG_VHOST_IOTLB=m and CONFIG_VHOST_RING=y, which
> makes the iotlb implementation left out from vhost_ring, and in turn
> leads to a link failure of the vdpa_sim module:
>
> ERROR: modpost: "vringh_set_iotlb" [drivers/vdpa/vdpa_sim/vdpa_sim.ko] undefined!
> ERROR: modpost: "vringh_init_iotlb" [drivers/vdpa/vdpa_sim/vdpa_sim.ko] undefined!
> ERROR: modpost: "vringh_iov_push_iotlb" [drivers/vdpa/vdpa_sim/vdpa_sim.ko] undefined!
> ERROR: modpost: "vringh_iov_pull_iotlb" [drivers/vdpa/vdpa_sim/vdpa_sim.ko] undefined!
> ERROR: modpost: "vringh_complete_iotlb" [drivers/vdpa/vdpa_sim/vdpa_sim.ko] undefined!
> ERROR: modpost: "vringh_getdesc_iotlb" [drivers/vdpa/vdpa_sim/vdpa_sim.ko] undefined!
>
> Work around it by setting the default for VHOST_IOTLB to avoid this
> configuration.
>
> Fixes: e6faeaa12841 ("vhost: drop vring dependency on iotlb")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> I fixed this a while ago locally but never got around to sending the
> fix. If the problem has been addressed differently in the meantime,
> please ignore this one.
So I ended up not sending e6faeaa12841 upstream because of this problem.
But hey, that's a nice idea!
I'll queue something like this for the next release.
> ---
> drivers/vhost/Kconfig | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
> index 2c75d164b827..ee5f85761024 100644
> --- a/drivers/vhost/Kconfig
> +++ b/drivers/vhost/Kconfig
> @@ -1,6 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0-only
> config VHOST_IOTLB
> tristate
> + default y if VHOST=m && VHOST_RING=y
> help
> Generic IOTLB implementation for vhost and vringh.
> This option is selected by any driver which needs to support
> --
> 2.26.0
