[net-next PATCH 4/4] samples/bpf: export map_data[] for more info on maps

[Jesper Dangaard Brouer <brouer@redhat.com>]

Giving *_user.c side tools access to map_data[] provides easier
access to information on the maps being loaded.  Still provide
the guarantee that the order maps are being defined in inside the
_kern.c file corresponds with the order in the array.  Now user
tools are not blind, but can inspect and verify the maps that got
loaded from the ELF binary.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
---
 samples/bpf/bpf_load.h |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/samples/bpf/bpf_load.h b/samples/bpf/bpf_load.h
index 4d4fd4678a64..ca0563d04744 100644
--- a/samples/bpf/bpf_load.h
+++ b/samples/bpf/bpf_load.h
@@ -24,12 +24,18 @@ struct bpf_map_data {
 
 typedef void (*fixup_map_cb)(struct bpf_map_data *map, int idx);
 
-extern int map_fd[MAX_MAPS];
 extern int prog_fd[MAX_PROGS];
 extern int event_fd[MAX_PROGS];
 extern char bpf_log_buf[BPF_LOG_BUF_SIZE];
 extern int prog_cnt;
 
+/* There is a one-to-one mapping between map_fd[] and map_data[].
+ * The map_data[] just contains more rich info on the given map.
+ */
+extern int map_fd[MAX_MAPS];
+extern struct bpf_map_data map_data[MAX_MAPS];
+extern int map_data_count;
+
 /* parses elf file compiled by llvm .c->.o
  * . parses 'maps' section and creates maps via BPF syscall
  * . parses 'license' section and passes it to syscall