[PATCH v3 2/2] net/af-xdp: Fix up cleanup path upon failure in queue creation

[Daniel Borkmann]

While testing, it turned out that upon error in the queue creation loop,
we never trigger the af_xdp_cleanup() handler. This is because we pass
errp instead of a local err pointer into the various AF_XDP setup functions
instead of a scheme like:

    bool fn(..., Error **errp)
    {
        Error *err = NULL;

        foo(arg, &err);
        if (err) {
            handle the error...
            error_propagate(errp, err);
            return false;
        }
        ...
    }

With a conversion into the above format, the af_xdp_cleanup() handler is
called as expected. Also, making sure the XDP program will be removed does
require to set s->n_queues to i + 1 since the test is nc->queue_index ==
s->n_queues - 1, where nc->queue_index was set to i earlier. With both
fixed the cleanup triggers as expected. Note the error_propagate() handles
a NULL err internally.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Ilya Maximets <i.maximets@ovn.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Anton Protopopov <aspsk@isovalent.com>
---
 net/af-xdp.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/af-xdp.c b/net/af-xdp.c
index b83d9bc47f..5d9857fdd8 100644
--- a/net/af-xdp.c
+++ b/net/af-xdp.c
@@ -559,12 +559,11 @@ int net_init_af_xdp(const Netdev *netdev,
             s->map_start_index = opts->map_start_index;
         }
 
-        if (af_xdp_umem_create(s, sock_fds ? sock_fds[i] : -1, errp) ||
-            af_xdp_socket_create(s, opts, errp) ||
-            af_xdp_update_xsk_map(s, errp)) {
+        if (af_xdp_umem_create(s, sock_fds ? sock_fds[i] : -1, &err) ||
+            af_xdp_socket_create(s, opts, &err) ||
+            af_xdp_update_xsk_map(s, &err)) {
             /* Make sure the XDP program will be removed. */
-            s->n_queues = i;
-            error_propagate(errp, err);
+            s->n_queues = i + 1;
             goto err;
         }
     }
@@ -586,6 +585,7 @@ int net_init_af_xdp(const Netdev *netdev,
 err:
     if (nc0) {
         qemu_del_net_client(nc0);
+        error_propagate(errp, err);
     }
 
     return -1;
-- 
2.43.0