bpftool: Mount bpffs when pinmaps path not under the bpffs

[ Upstream commit da5f8fd ]

As Quentin said [0], BPF map pinning will fail if the pinmaps path is not
under the bpffs, like:

  libbpf: specified path /home/ubuntu/test/sock_ops_map is not on BPF FS
  Error: failed to pin all maps

  [0] libbpf/bpftool#146

Fixes: 3767a94 ("bpftool: add pinmaps argument to the load/loadall")
Signed-off-by: Tao Chen <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Tested-by: Quentin Monnet <[email protected]>
Reviewed-by: Quentin Monnet <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>

Author: chentao-kernel

tools/bpf/bpftool/prog.c

@@ -1809,6 +1809,10 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
 	}
 
 	if (pinmaps) {
+		err = create_and_mount_bpffs_dir(pinmaps);
+		if (err)
+			goto err_unpin;
+
 		err = bpf_object__pin_maps(obj, pinmaps);
 		if (err) {
 			p_err("failed to pin all maps");