[PATCH bpf-next v1 2/4] bpf: frame_insn_idx() utility function

[Eduard Zingerman <eddyz87@gmail.com>]

A function to return IP for a given frame in a call stack of a state.
Will be used by a next patch.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
 kernel/bpf/verifier.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9d1f912c12a8..67903270b217 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -18235,6 +18235,14 @@ static void clean_verifier_state(struct bpf_verifier_env *env,
 		clean_func_state(env, st->frame[i]);
 }
 
+/* Return IP for a given frame in a call stack */
+static u32 frame_insn_idx(struct bpf_verifier_state *st, u32 frame)
+{
+	return frame == st->curframe
+	       ? st->insn_idx
+	       : st->frame[frame + 1]->callsite;
+}
+
 /* the parentage chains form a tree.
  * the verifier states are added to state lists at given insn and
  * pushed into state stack for future exploration.
@@ -18731,9 +18739,7 @@ static bool states_equal(struct bpf_verifier_env *env,
 	 * and all frame states need to be equivalent
 	 */
 	for (i = 0; i <= old->curframe; i++) {
-		insn_idx = i == old->curframe
-			   ? env->insn_idx
-			   : old->frame[i + 1]->callsite;
+		insn_idx = frame_insn_idx(old, i);
 		if (old->frame[i]->callsite != cur->frame[i]->callsite)
 			return false;
 		if (!func_states_equal(env, old->frame[i], cur->frame[i], insn_idx, exact))
-- 
2.48.1