qemu-stable
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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


From: Jonah Palmer
Subject: Re: [PATCH v2 0/2] Move net backend cleanup to NIC cleanup
Date: Mon, 6 Jan 2025 11:03:47 -0500
User-agent: Mozilla Thunderbird



On 12/23/24 11:33 AM, Eugenio Perez Martin wrote:
On Fri, Dec 20, 2024 at 10:02 PM Michael Tokarev <mjt@tls.msk.ru> wrote:

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?


I guess it is better to resend a v3, so we don't have a compiler
warning (or error). Jonah, maybe do you want to move this one forward?

Thanks!

Just sent out the v3 with the quick fix.

Ugh, and I just realized I forgot to CC Michael Tokarev in the v3 series. My apologies Michael!

Jonah




reply via email to

[Prev in Thread] Current Thread [Next in Thread]