bpf: Add is_fd_htab() helper

Add is_fd_htab() helper to check whether the map is htab of maps.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20250401062250.543403-5-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 4879c79dd6776b74038cb7deea8c600e019c0fd2..097992efef05f544a0e4f16f6ed521d4b33ab7f7 100644 (file)
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -175,6 +175,11 @@ static bool htab_is_percpu(const struct bpf_htab *htab)
                htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
 }
 
+static inline bool is_fd_htab(const struct bpf_htab *htab)
+{
+       return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS;
+}
+
 static inline void *htab_elem_value(struct htab_elem *l, u32 key_size)
 {
        return l->key + round_up(key_size, 8);
@@ -974,8 +979,7 @@ static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr,
 
 static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
 {
-       return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
-              BITS_PER_LONG == 64;
+       return is_fd_htab(htab) && BITS_PER_LONG == 64;
 }
 
 static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
@@ -1810,7 +1814,7 @@ again_nocopy:
                        }
                } else {
                        value = htab_elem_value(l, key_size);
-                       if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
+                       if (is_fd_htab(htab)) {
                                struct bpf_map **inner_map = value;
 
                                 /* Actual value is the id of the inner map */