bpf: report offload info to user space

Extend struct bpf_prog_info to contain information about program
being bound to a device.  Since the netdev may get destroyed while
program still exists we need a flag to indicate the program is
loaded for a device, even if the device is gone.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 1574b9f0f24e..3217c20ea91b 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1592,6 +1592,11 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
                         return -EFAULT;
         }
 
+        if (bpf_prog_is_dev_bound(prog->aux)) {
+                info.status |= BPF_PROG_STATUS_DEV_BOUND;
+                info.ifindex = bpf_prog_offload_ifindex(prog);
+        }
+
 done:
         if (copy_to_user(uinfo, &info, info_len) ||
             put_user(info_len, &uattr->info.info_len))