[dpdk-dev] [PATCH v2 1/1] vhost: fix leak of fds and mmaps
Yuanhan Liu
yuanhan.liu at linux.intel.com
Mon Jan 18 08:58:08 CET 2016
On Sun, Jan 17, 2016 at 11:57:18AM -0800, Rich Lane wrote:
> The common vhost code only supported a single mmap per device. vhost-user
> worked around this by saving the address/length/fd of each mmap after the end
> of the rte_virtio_memory struct. This only works if the vhost-user code frees
> dev->mem, since the common code is unaware of the extra info. The
> VHOST_USER_RESET_OWNER message is one situation where the common code frees
> dev->mem and leaks the fds and mappings. This happens every time I shut down a
> VM.
>
> The new code calls back into the implementation (vhost-user or vhost-cuse) to
> clean up these resources.
>
> The vhost-cuse changes are only compile tested.
>
> Signed-off-by: Rich Lane <rlane at bigswitch.com>
> ---
> v1->v2:
> - Call into vhost-user/vhost-cuse to free mmaps.
>
> lib/librte_vhost/vhost-net.h | 6 ++++++
> lib/librte_vhost/vhost_cuse/virtio-net-cdev.c | 12 ++++++++++++
> lib/librte_vhost/vhost_user/vhost-net-user.c | 1 -
> lib/librte_vhost/vhost_user/virtio-net-user.c | 25 ++++++++++---------------
> lib/librte_vhost/vhost_user/virtio-net-user.h | 1 -
> lib/librte_vhost/virtio-net.c | 8 +-------
> 6 files changed, 29 insertions(+), 24 deletions(-)
>
> diff --git a/lib/librte_vhost/vhost-net.h b/lib/librte_vhost/vhost-net.h
> index c69b60b..e8d7477 100644
> --- a/lib/librte_vhost/vhost-net.h
> +++ b/lib/librte_vhost/vhost-net.h
> @@ -115,4 +115,10 @@ struct vhost_net_device_ops {
>
>
> struct vhost_net_device_ops const *get_virtio_net_callbacks(void);
> +
> +/*
> + * Implementation-specific cleanup. Defined by vhost-cuse and vhost-user.
> + */
> +void vhost_impl_cleanup(struct virtio_net *dev);
TBH, I am not quite like "_impl_"; maybe "_backend_" is better?
OTOH, what I thought of has slight difference than yours: not
necessary to export a function, but instead, call the vhost
backend specific unmap function inside the backend itself. Say,
call vhost_user_unmap() on RESET_OWNER and connection close.
What do you think of that?
--yliu
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