[PATCH bpf-next 1/3] bpf: Factor out nullable reg type conversion

[Dmitrii Banshchikov <me@ubique.spb.ru>]

Factor out helper function for conversion nullable register type to its
corresponding type with value.

Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
---
 kernel/bpf/verifier.c | 77 ++++++++++++++++++++++++-------------------
 1 file changed, 44 insertions(+), 33 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 93def76cf32b..dee296dbc7a1 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1073,6 +1073,43 @@ static void mark_reg_known_zero(struct bpf_verifier_env *env,
 	__mark_reg_known_zero(regs + regno);
 }
 
+static int mark_ptr_not_null_reg(struct bpf_reg_state *reg)
+{
+	if (reg->type == PTR_TO_MAP_VALUE_OR_NULL) {
+		const struct bpf_map *map = reg->map_ptr;
+
+		if (map->inner_map_meta) {
+			reg->type = CONST_PTR_TO_MAP;
+			reg->map_ptr = map->inner_map_meta;
+		} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
+			reg->type = PTR_TO_XDP_SOCK;
+		} else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||
+			   map->map_type == BPF_MAP_TYPE_SOCKHASH) {
+			reg->type = PTR_TO_SOCKET;
+		} else {
+			reg->type = PTR_TO_MAP_VALUE;
+		}
+	} else if (reg->type == PTR_TO_SOCKET_OR_NULL) {
+		reg->type = PTR_TO_SOCKET;
+	} else if (reg->type == PTR_TO_SOCK_COMMON_OR_NULL) {
+		reg->type = PTR_TO_SOCK_COMMON;
+	} else if (reg->type == PTR_TO_TCP_SOCK_OR_NULL) {
+		reg->type = PTR_TO_TCP_SOCK;
+	} else if (reg->type == PTR_TO_BTF_ID_OR_NULL) {
+		reg->type = PTR_TO_BTF_ID;
+	} else if (reg->type == PTR_TO_MEM_OR_NULL) {
+		reg->type = PTR_TO_MEM;
+	} else if (reg->type == PTR_TO_RDONLY_BUF_OR_NULL) {
+		reg->type = PTR_TO_RDONLY_BUF;
+	} else if (reg->type == PTR_TO_RDWR_BUF_OR_NULL) {
+		reg->type = PTR_TO_RDWR_BUF;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
 {
 	return type_is_pkt_pointer(reg->type);
@@ -7323,50 +7360,24 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state,
 		}
 		if (is_null) {
 			reg->type = SCALAR_VALUE;
-		} else if (reg->type == PTR_TO_MAP_VALUE_OR_NULL) {
-			const struct bpf_map *map = reg->map_ptr;
-
-			if (map->inner_map_meta) {
-				reg->type = CONST_PTR_TO_MAP;
-				reg->map_ptr = map->inner_map_meta;
-			} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
-				reg->type = PTR_TO_XDP_SOCK;
-			} else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||
-				   map->map_type == BPF_MAP_TYPE_SOCKHASH) {
-				reg->type = PTR_TO_SOCKET;
-			} else {
-				reg->type = PTR_TO_MAP_VALUE;
-			}
-		} else if (reg->type == PTR_TO_SOCKET_OR_NULL) {
-			reg->type = PTR_TO_SOCKET;
-		} else if (reg->type == PTR_TO_SOCK_COMMON_OR_NULL) {
-			reg->type = PTR_TO_SOCK_COMMON;
-		} else if (reg->type == PTR_TO_TCP_SOCK_OR_NULL) {
-			reg->type = PTR_TO_TCP_SOCK;
-		} else if (reg->type == PTR_TO_BTF_ID_OR_NULL) {
-			reg->type = PTR_TO_BTF_ID;
-		} else if (reg->type == PTR_TO_MEM_OR_NULL) {
-			reg->type = PTR_TO_MEM;
-		} else if (reg->type == PTR_TO_RDONLY_BUF_OR_NULL) {
-			reg->type = PTR_TO_RDONLY_BUF;
-		} else if (reg->type == PTR_TO_RDWR_BUF_OR_NULL) {
-			reg->type = PTR_TO_RDWR_BUF;
-		}
-		if (is_null) {
 			/* We don't need id and ref_obj_id from this point
 			 * onwards anymore, thus we should better reset it,
 			 * so that state pruning has chances to take effect.
 			 */
 			reg->id = 0;
 			reg->ref_obj_id = 0;
-		} else if (!reg_may_point_to_spin_lock(reg)) {
-			/* For not-NULL ptr, reg->ref_obj_id will be reset
+		} else {
+			mark_ptr_not_null_reg(reg);
+
+			if (!reg_may_point_to_spin_lock(reg)) {
+				/* For not-NULL ptr, reg->ref_obj_id will be reset
 			 * in release_reg_references().
 			 *
 			 * reg->id is still used by spin_lock ptr. Other
 			 * than spin_lock ptr type, reg->id can be reset.
 			 */
-			reg->id = 0;
+				reg->id = 0;
+			}
 		}
 	}
 }
-- 
2.25.1