Re: linux-next: manual merge of the bpf-next tree with Linus' tree

[Stanislav Fomichev]

On Mon, Jan 23, 2023 at 2:44 PM Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> Hi all,
>
> Today's linux-next merge of the bpf-next tree got a conflict in:
>
>   kernel/bpf/offload.c
>
> between commit:
>
>   ef01f4e25c17 ("bpf: restore the ebpf program ID for BPF_AUDIT_UNLOAD and PERF_BPF_EVENT_PROG_UNLOAD")
>
> from Linus' tree and commit:
>
>   89bbc53a4dbb ("bpf: Reshuffle some parts of bpf/offload.c")
>
> from the bpf-next tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.

Yeah, that looks like a correct resolution, thank you!
Not sure what would've been the correct way to handle it in bpf-next
(except waiting for bpf tree to be merged)?

> --
> Cheers,
> Stephen Rothwell
>
> diff --cc kernel/bpf/offload.c
> index 190d9f9dc987,e87cab2ed710..000000000000
> --- a/kernel/bpf/offload.c
> +++ b/kernel/bpf/offload.c
> @@@ -75,20 -74,124 +74,121 @@@ bpf_offload_find_netdev(struct net_devi
>         return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
>   }
>
> - int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
> + static int __bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
> +                                            struct net_device *netdev)
>   {
>         struct bpf_offload_netdev *ondev;
> -       struct bpf_prog_offload *offload;
>         int err;
>
> -       if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS &&
> -           attr->prog_type != BPF_PROG_TYPE_XDP)
> -               return -EINVAL;
> +       ondev = kzalloc(sizeof(*ondev), GFP_KERNEL);
> +       if (!ondev)
> +               return -ENOMEM;
>
> -       if (attr->prog_flags)
> -               return -EINVAL;
> +       ondev->netdev = netdev;
> +       ondev->offdev = offdev;
> +       INIT_LIST_HEAD(&ondev->progs);
> +       INIT_LIST_HEAD(&ondev->maps);
> +
> +       err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params);
> +       if (err) {
> +               netdev_warn(netdev, "failed to register for BPF offload\n");
> +               goto err_free;
> +       }
> +
> +       if (offdev)
> +               list_add(&ondev->offdev_netdevs, &offdev->netdevs);
> +       return 0;
> +
> + err_free:
> +       kfree(ondev);
> +       return err;
> + }
> +
> + static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
> + {
> +       struct bpf_prog_offload *offload = prog->aux->offload;
> +
> +       if (offload->dev_state)
> +               offload->offdev->ops->destroy(prog);
> +
>  -      /* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */
>  -      bpf_prog_free_id(prog, true);
>  -
> +       list_del_init(&offload->offloads);
> +       kfree(offload);
> +       prog->aux->offload = NULL;
> + }
> +
> + static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap,
> +                              enum bpf_netdev_command cmd)
> + {
> +       struct netdev_bpf data = {};
> +       struct net_device *netdev;
> +
> +       ASSERT_RTNL();
> +
> +       data.command = cmd;
> +       data.offmap = offmap;
> +       /* Caller must make sure netdev is valid */
> +       netdev = offmap->netdev;
> +
> +       return netdev->netdev_ops->ndo_bpf(netdev, &data);
> + }
> +
> + static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap)
> + {
> +       WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE));
> +       /* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */
> +       bpf_map_free_id(&offmap->map, true);
> +       list_del_init(&offmap->offloads);
> +       offmap->netdev = NULL;
> + }
> +
> + static void __bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
> +                                               struct net_device *netdev)
> + {
> +       struct bpf_offload_netdev *ondev, *altdev = NULL;
> +       struct bpf_offloaded_map *offmap, *mtmp;
> +       struct bpf_prog_offload *offload, *ptmp;
> +
> +       ASSERT_RTNL();
> +
> +       ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
> +       if (WARN_ON(!ondev))
> +               return;
> +
> +       WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params));
> +
> +       /* Try to move the objects to another netdev of the device */
> +       if (offdev) {
> +               list_del(&ondev->offdev_netdevs);
> +               altdev = list_first_entry_or_null(&offdev->netdevs,
> +                                                 struct bpf_offload_netdev,
> +                                                 offdev_netdevs);
> +       }
> +
> +       if (altdev) {
> +               list_for_each_entry(offload, &ondev->progs, offloads)
> +                       offload->netdev = altdev->netdev;
> +               list_splice_init(&ondev->progs, &altdev->progs);
> +
> +               list_for_each_entry(offmap, &ondev->maps, offloads)
> +                       offmap->netdev = altdev->netdev;
> +               list_splice_init(&ondev->maps, &altdev->maps);
> +       } else {
> +               list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads)
> +                       __bpf_prog_offload_destroy(offload->prog);
> +               list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads)
> +                       __bpf_map_offload_destroy(offmap);
> +       }
> +
> +       WARN_ON(!list_empty(&ondev->progs));
> +       WARN_ON(!list_empty(&ondev->maps));
> +       kfree(ondev);
> + }
> +
> + static int __bpf_prog_dev_bound_init(struct bpf_prog *prog, struct net_device *netdev)
> + {
> +       struct bpf_offload_netdev *ondev;
> +       struct bpf_prog_offload *offload;
> +       int err;
>
>         offload = kzalloc(sizeof(*offload), GFP_USER);
>         if (!offload)