[PATCH v5 2/3] net/af-xdp: Fix up cleanup path upon failure in queue creation

[Daniel Borkmann via <qemu-devel@nongnu.org>]

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;
        }
        ...
    }

The same is true for the attachment probing with bpf_xdp_query_id(). With a
conversion into the above format, the af_xdp_cleanup() handler is called as
expected. Note the error_propagate() handles a NULL err internally.

Fixes: cb039ef3d9e3 ("net: add initial support for AF_XDP network backend")
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 | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/af-xdp.c b/net/af-xdp.c
index c5d3b6a953..1692efe9f2 100644
--- a/net/af-xdp.c
+++ b/net/af-xdp.c
@@ -482,9 +482,8 @@ int net_init_af_xdp(const Netdev *netdev,
         pstrcpy(s->ifname, sizeof(s->ifname), opts->ifname);
         s->ifindex = ifindex;
 
-        if (af_xdp_umem_create(s, sock_fds ? sock_fds[i] : -1, errp)
-            || af_xdp_socket_create(s, opts, errp)) {
-            error_propagate(errp, err);
+        if (af_xdp_umem_create(s, sock_fds ? sock_fds[i] : -1, &err) ||
+            af_xdp_socket_create(s, opts, &err)) {
             goto err;
         }
     }
@@ -492,7 +491,7 @@ int net_init_af_xdp(const Netdev *netdev,
     if (nc0) {
         s = DO_UPCAST(AFXDPState, nc, nc0);
         if (bpf_xdp_query_id(s->ifindex, s->xdp_flags, &prog_id) || !prog_id) {
-            error_setg_errno(errp, errno,
+            error_setg_errno(&err, errno,
                              "no XDP program loaded on '%s', ifindex: %d",
                              s->ifname, s->ifindex);
             goto err;
@@ -506,6 +505,7 @@ 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