From: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Date: Tue, 9 Oct 2018 10:04:50 +0900
Subject: bpf: return EOPNOTSUPP when map lookup isn't supported
Patch-mainline: v4.20-rc1
Git-commit: 3b4a63f674e94795c9b76a41b36364b8aec232e1
References: bsc#1109837

Return ERR_PTR(-EOPNOTSUPP) from map_lookup_elem() methods of below
map types:
- BPF_MAP_TYPE_PROG_ARRAY
- BPF_MAP_TYPE_STACK_TRACE
- BPF_MAP_TYPE_XSKMAP
- BPF_MAP_TYPE_SOCKMAP/BPF_MAP_TYPE_SOCKHASH

Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 kernel/bpf/arraymap.c |    2 +-
 kernel/bpf/sockmap.c  |    2 +-
 kernel/bpf/stackmap.c |    2 +-
 kernel/bpf/xskmap.c   |    2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -431,7 +431,7 @@ static void fd_array_map_free(struct bpf
 
 static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
 {
-	return NULL;
+	return ERR_PTR(-EOPNOTSUPP);
 }
 
 /* only called from syscall */
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -2078,7 +2078,7 @@ int sock_map_prog(struct bpf_map *map, s
 
 static void *sock_map_lookup(struct bpf_map *map, void *key)
 {
-	return NULL;
+	return ERR_PTR(-EOPNOTSUPP);
 }
 
 static int sock_map_update_elem(struct bpf_map *map,
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -505,7 +505,7 @@ const struct bpf_func_proto bpf_get_stac
 /* Called from eBPF program */
 static void *stack_map_lookup_elem(struct bpf_map *map, void *key)
 {
-	return NULL;
+	return ERR_PTR(-EOPNOTSUPP);
 }
 
 /* Called from syscall */
--- a/kernel/bpf/xskmap.c
+++ b/kernel/bpf/xskmap.c
@@ -154,7 +154,7 @@ void __xsk_map_flush(struct bpf_map *map
 
 static void *xsk_map_lookup_elem(struct bpf_map *map, void *key)
 {
-	return NULL;
+	return ERR_PTR(-EOPNOTSUPP);
 }
 
 static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,