Subject: [PATCH bpf-next 1/3] bpf: cleanup explored_states

From: Alexei Starovoitov <[email-masked]>
Date: Tue, 21 May 2019 16:06:33 -0700

clean up explored_states to prep for introduction of hashtable
No functional changes.

Signed-off-by: Alexei Starovoitov <[email-masked]>
---
 kernel/bpf/verifier.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 95f9354495ad..a171b2940382 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5436,6 +5436,18 @@ enum {
 };
 
 #define STATE_LIST_MARK ((struct bpf_verifier_state_list *) -1L)
+static struct bpf_verifier_state_list **explored_state(
+					struct bpf_verifier_env *env,
+					int idx)
+{
+	return &env->explored_states[idx];
+}
+
+static void init_explored_state(struct bpf_verifier_env *env, int idx)
+{
+	env->explored_states[idx] = STATE_LIST_MARK;
+}
+
 
 /* t, w, e - match pseudo-code above:
  * t - index of current instruction
@@ -5461,7 +5473,7 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env)
 
 	if (e == BRANCH)
 		/* mark branch target for state pruning */
-		env->explored_states[w] = STATE_LIST_MARK;
+		init_explored_state(env, w);
 
 	if (insn_state[w] == 0) {
 		/* tree-edge */
@@ -5529,9 +5541,9 @@ static int check_cfg(struct bpf_verifier_env *env)
 			else if (ret < 0)
 				goto err_free;
 			if (t + 1 < insn_cnt)
-				env->explored_states[t + 1] = STATE_LIST_MARK;
+				init_explored_state(env, t + 1);
 			if (insns[t].src_reg == BPF_PSEUDO_CALL) {
-				env->explored_states[t] = STATE_LIST_MARK;
+				init_explored_state(env, t);
 				ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env);
 				if (ret == 1)
 					goto peek_stack;
@@ -5554,10 +5566,10 @@ static int check_cfg(struct bpf_verifier_env *env)
 			 * after every call and jump
 			 */
 			if (t + 1 < insn_cnt)
-				env->explored_states[t + 1] = STATE_LIST_MARK;
+				init_explored_state(env, t + 1);
 		} else {
 			/* conditional jump with two edges */
-			env->explored_states[t] = STATE_LIST_MARK;
+			init_explored_state(env, t);
 			ret = push_insn(t, t + 1, FALLTHROUGH, env);
 			if (ret == 1)
 				goto peek_stack;
@@ -6005,7 +6017,7 @@ static void clean_live_states(struct bpf_verifier_env *env, int insn,
 	struct bpf_verifier_state_list *sl;
 	int i;
 
-	sl = env->explored_states[insn];
+	sl = *explored_state(env, insn);
 	if (!sl)
 		return;
 
@@ -6364,7 +6376,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
 	struct bpf_verifier_state *cur = env->cur_state, *new;
 	int i, j, err, states_cnt = 0;
 
-	pprev = &env->explored_states[insn_idx];
+	pprev = explored_state(env, insn_idx);
 	sl = *pprev;
 
 	if (!sl)
@@ -6451,8 +6463,8 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
 		kfree(new_sl);
 		return err;
 	}
-	new_sl->next = env->explored_states[insn_idx];
-	env->explored_states[insn_idx] = new_sl;
+	new_sl->next = *explored_state(env, insn_idx);
+	*explored_state(env, insn_idx) = new_sl;
 	/* connect new state to parentage chain. Current frame needs all
 	 * registers connected. Only r6 - r9 of the callers are alive (pushed
 	 * to the stack implicitly by JITs) so in callers' frames connect just
-- 
2.20.0