[PATCH bpf-next] bpf: Return EINVAL instead of NULL for map_lookup_elem of queue

[Florian Lehner <dev@der-flo.net>]

Programs should use map_peek_elem over map_lookup_elem for queues. NULL is
also not a valid queue return nor a proper error, that could be handled.

Signed-off-by: Florian Lehner <dev@der-flo.net>
---
 kernel/bpf/queue_stack_maps.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c
index d869f51ea93a..85bead55024d 100644
--- a/kernel/bpf/queue_stack_maps.c
+++ b/kernel/bpf/queue_stack_maps.c
@@ -234,7 +234,8 @@ static long queue_stack_map_push_elem(struct bpf_map *map, void *value,
 /* Called from syscall or from eBPF program */
 static void *queue_stack_map_lookup_elem(struct bpf_map *map, void *key)
 {
-	return NULL;
+	/* The eBPF program should use map_peek_elem instead */
+	return ERR_PTR(-EINVAL);
 }
 
 /* Called from syscall or from eBPF program */
-- 
2.45.2