From: Hou Tao <houtao1@xxxxxxxxxx>
bpf_map_of_map_fd_sys_lookup_elem() returns the map id as the value for
map-in-map. It will be used when userspace applications do lookup
operations for map-in-map.
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
kernel/bpf/map_in_map.c | 6 ++++++
kernel/bpf/map_in_map.h | 1 +
2 files changed, 7 insertions(+)
diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c
index 96e32f4167c4e..3cd08e7fb86e6 100644
--- a/kernel/bpf/map_in_map.c
+++ b/kernel/bpf/map_in_map.c
@@ -190,3 +190,9 @@ void bpf_map_of_map_fd_put_ptr(void *ptr, bool need_defer)
else
bpf_inner_map_element_free_rcu(&element->rcu);
}
+
+u32 bpf_map_of_map_fd_sys_lookup_elem(void *ptr)
+{
+ rcu_read_lock_held();
+ return ((struct bpf_inner_map_element *)ptr)->map->id;
+}
diff --git a/kernel/bpf/map_in_map.h b/kernel/bpf/map_in_map.h
index 8d38496e5179b..4a0d66757a065 100644
--- a/kernel/bpf/map_in_map.h
+++ b/kernel/bpf/map_in_map.h
@@ -22,5 +22,6 @@ u32 bpf_map_fd_sys_lookup_elem(void *ptr);
void *bpf_map_of_map_fd_get_ptr(struct bpf_map *map, struct file *map_file, int ufd);
void bpf_map_of_map_fd_put_ptr(void *ptr, bool need_defer);
+u32 bpf_map_of_map_fd_sys_lookup_elem(void *ptr);
#endif
--
2.29.2
