Check if key supports batch API in Map() ctor (#32348)

pkg/ebpf/maps/generic_map.go

@@ -130,8 +130,17 @@ func Map[K any, V any](m *ebpf.Map) (*GenericMap[K, V], error) {
 		return nil, err
 	}
 
+	// See if we can perform binary.Read on the key type. If we can't we can't use the batch API
+	// for this map
+	var kval K
+	keySupportsBatchAPI := canBinaryReadKey[K]()
+	if !keySupportsBatchAPI {
+		log.Warnf("Key type %T does not support binary.Read, batch API will not be used for this map", kval)
+	}
+
 	return &GenericMap[K, V]{
-		m: m,
+		m:                   m,
+		keySupportsBatchAPI: keySupportsBatchAPI,
 	}, nil
 }
 

pkg/ebpf/maps/generic_map_test.go

@@ -572,3 +572,19 @@ func TestIterateWithPointerKey(t *testing.T) {
 	require.NoError(t, it.Err())
 	require.Equal(t, expectedNumbers, actualNumbers)
 }
+
+func TestGenericHashMapCanUseBatchAPI(t *testing.T) {
+	hash, err := ebpf.NewMap(&ebpf.MapSpec{
+		Type:       ebpf.Hash,
+		KeySize:    4,
+		ValueSize:  4,
+		MaxEntries: 10,
+	})
+	require.NoError(t, err)
+	t.Cleanup(func() { hash.Close() })
+
+	gm, err := Map[int32, int32](hash)
+	require.NoError(t, err)
+
+	require.Equal(t, BatchAPISupported(), gm.CanUseBatchAPI())
+}