Re: [PATCH v2 0/2] Move net backend cleanup to NIC cleanup

[Michael Tokarev]

12.09.2024 19:54, Eugenio Pérez wrote:
> Commit a0d7215e33 ("vhost-vdpa: do not cleanup the vdpa/vhost-net
> structures if peer nic is present") effectively delayed the backend
> cleanup, allowing the frontend or the guest to access it resources as
> long as the frontend NIC is still visible to the guest.
>
> However it does not clean up the resources until the qemu process is
> over.  This causes an effective leak if the device is deleted with
> device_del, as there is no way to close the vdpa device.  This makes
> impossible to re-add that device to this or other QEMU instances until
> the first instance of QEMU is finished.
>
> Move the cleanup from qemu_cleanup to the NIC deletion.
>
> v2:
> Remove NIC peer also at net_cleanup. vhost-user trust all the
> backends are clean before qemu removes char devices.
>
> This is not a requisite introduced by this commit as
> system/runstate.c:qemu_cleanup shows.
>
> Eugenio Pérez (2):
>    net: parameterize the removing client from nc list
>    net: move backend cleanup to NIC cleanup
>
>   net/net.c        | 44 ++++++++++++++++++++++++++++++++++----------
>   net/vhost-vdpa.c |  8 --------
>   2 files changed, 34 insertions(+), 18 deletions(-)
Hi!

It looks like this series has been forgotten.  Is it still needed?

In order for it to build, a single line in patch 2 needs to be
changed (in net_cleanup()), from:

+                for (int i = 0; i < queues; i++) {
+                    NetClientState *nc = qemu_get_subqueue(nic, i);
+                    qemu_cleanup_net_client(nc->peer, false);
+                }

to

+                for (int i = 0; i < queues; i++) {
+                    nc = qemu_get_subqueue(nic, i);
+                    qemu_cleanup_net_client(nc->peer, false);
+                }

so there's no variable shadowing anymore.

Should this series be resent (a v3), or can this be fixed at apply time?

Thanks,