Fix BufferHub state machine to return errors on invalid transitions.
The consumer side of the BufferHub flow did not have an adequate
state machine to track transitions and return errors when Acquire
or Release are requested from the wrong state. This bug allowed
other buggy usage to go unnoticed.
- Fix the consumer state machine to correctly validate all requests.
- Add tests to verify correctness of the fix.
Tested BufferHub with the new test before and after the fix and
verified that the test catches the problem and that the fix solves
the problem.
Bug: 62886596
Bug: 63149525
Test: bufferhub_tests passes.
Change-Id: I802679ed74c7f505b9243ba4048824350d4e37be
diff --git a/libs/vr/libbufferhub/bufferhub_tests.cpp b/libs/vr/libbufferhub/bufferhub_tests.cpp
index fa61c4a..1daa5d6 100644
--- a/libs/vr/libbufferhub/bufferhub_tests.cpp
+++ b/libs/vr/libbufferhub/bufferhub_tests.cpp
@@ -62,6 +62,57 @@
EXPECT_GE(0, RETRY_EINTR(p->Poll(0)));
}
+TEST_F(LibBufferHubTest, TestStateTransitions) {
+ std::unique_ptr<BufferProducer> p = BufferProducer::Create(
+ kWidth, kHeight, kFormat, kUsage, sizeof(uint64_t));
+ ASSERT_TRUE(p.get() != nullptr);
+ std::unique_ptr<BufferConsumer> c =
+ BufferConsumer::Import(p->CreateConsumer());
+ ASSERT_TRUE(c.get() != nullptr);
+
+ uint64_t context;
+ LocalHandle fence;
+
+ // The producer buffer starts in gained state.
+
+ // Acquire, release, and gain in gained state should fail.
+ EXPECT_EQ(-EBUSY, c->Acquire(&fence, &context));
+ EXPECT_EQ(-EBUSY, c->Release(LocalHandle()));
+ EXPECT_EQ(-EALREADY, p->Gain(&fence));
+
+ // Post in gained state should succeed.
+ EXPECT_EQ(0, p->Post(LocalHandle(), kContext));
+
+ // Post, release, and gain in posted state should fail.
+ EXPECT_EQ(-EBUSY, p->Post(LocalHandle(), kContext));
+ EXPECT_EQ(-EBUSY, c->Release(LocalHandle()));
+ EXPECT_EQ(-EBUSY, p->Gain(&fence));
+
+ // Acquire in posted state should succeed.
+ EXPECT_LE(0, c->Acquire(&fence, &context));
+
+ // Acquire, post, and gain in acquired state should fail.
+ EXPECT_EQ(-EBUSY, c->Acquire(&fence, &context));
+ EXPECT_EQ(-EBUSY, p->Post(LocalHandle(), kContext));
+ EXPECT_EQ(-EBUSY, p->Gain(&fence));
+
+ // Release in acquired state should succeed.
+ EXPECT_EQ(0, c->Release(LocalHandle()));
+
+ // Release, acquire, and post in released state should fail.
+ EXPECT_EQ(-EBUSY, c->Release(LocalHandle()));
+ EXPECT_EQ(-EBUSY, c->Acquire(&fence, &context));
+ EXPECT_EQ(-EBUSY, p->Post(LocalHandle(), kContext));
+
+ // Gain in released state should succeed.
+ EXPECT_EQ(0, p->Gain(&fence));
+
+ // Acquire, release, and gain in gained state should fail.
+ EXPECT_EQ(-EBUSY, c->Acquire(&fence, &context));
+ EXPECT_EQ(-EBUSY, c->Release(LocalHandle()));
+ EXPECT_EQ(-EALREADY, p->Gain(&fence));
+}
+
TEST_F(LibBufferHubTest, TestWithCustomMetadata) {
struct Metadata {
int64_t field1;