libfmq: wait EventFlag before timeout check

Bug: 302036943
Test: atest --test-mapping system/libfmq:presubmit
Test: flash to Pixel and check media playback use cases
Change-Id: I1e0a816203aa71677103c5122ff785b4021d9ea5

2 files changed, 77 insertions, 5 deletions

diff --git a/EventFlag.cpp b/EventFlag.cpp
index d353873..8cf2760 100644
--- a/EventFlag.cpp
+++ b/EventFlag.cpp
@@ -171,6 +171,11 @@ status_t EventFlag::wait(uint32_t bitmask,
     int64_t prevTimeNs = shouldTimeOut ? android::elapsedRealtimeNano() : 0;
     status_t status;
     while (true) {
+        status = waitHelper(bitmask, efState, timeoutNanoSeconds);
+        if ((status != -EAGAIN) && (status != -EINTR)) {
+            break;
+        }
+
         if (shouldTimeOut) {
             int64_t currentTimeNs = android::elapsedRealtimeNano();
             /*
@@ -185,11 +190,6 @@ status_t EventFlag::wait(uint32_t bitmask,
                 break;
             }
         }
-
-        status = waitHelper(bitmask, efState, timeoutNanoSeconds);
-        if ((status != -EAGAIN) && (status != -EINTR)) {
-            break;
-        }
     }
     return status;
 }
diff --git a/tests/fmq_unit_tests.cpp b/tests/fmq_unit_tests.cpp
index 08790c8..96a8261 100644
--- a/tests/fmq_unit_tests.cpp
+++ b/tests/fmq_unit_tests.cpp
@@ -695,6 +695,78 @@ TYPED_TEST(BlockingReadWrites, BlockingTimeOutTest) {
 }
 
 /*
+ * Test EventFlag wait on a waked flag with a short timeout.
+ */
+TYPED_TEST(BlockingReadWrites, ShortEventFlagWaitWithWakeTest) {
+    std::atomic<uint32_t> eventFlagWord;
+    std::atomic_init(&eventFlagWord, static_cast<uint32_t>(kFmqNotFull));
+    android::hardware::EventFlag* efGroup = nullptr;
+    android::status_t status =
+            android::hardware::EventFlag::createEventFlag(&eventFlagWord, &efGroup);
+    ASSERT_EQ(android::NO_ERROR, status);
+    ASSERT_NE(nullptr, efGroup);
+
+    status = efGroup->wake(kFmqNotEmpty);
+    ASSERT_EQ(android::NO_ERROR, status);
+
+    uint32_t efState = 0;
+    android::status_t ret = efGroup->wait(kFmqNotEmpty, &efState, 1 /* ns */, true /* retry */);
+    ASSERT_EQ(android::NO_ERROR, ret);
+
+    status = android::hardware::EventFlag::deleteEventFlag(&efGroup);
+    ASSERT_EQ(android::NO_ERROR, status);
+}
+
+/*
+ * Test on an EventFlag with no wakeup, short timeout.
+ */
+TYPED_TEST(BlockingReadWrites, ShortEventFlagWaitWithoutWakeTest) {
+    std::atomic<uint32_t> eventFlagWord;
+    std::atomic_init(&eventFlagWord, static_cast<uint32_t>(kFmqNotFull));
+    android::hardware::EventFlag* efGroup = nullptr;
+    android::status_t status =
+            android::hardware::EventFlag::createEventFlag(&eventFlagWord, &efGroup);
+    ASSERT_EQ(android::NO_ERROR, status);
+    ASSERT_NE(nullptr, efGroup);
+
+    uint32_t efState = 0;
+    android::status_t ret = efGroup->wait(kFmqNotEmpty, &efState, 1 /* ns */, true /* retry */);
+    ASSERT_EQ(android::TIMED_OUT, ret);
+
+    status = android::hardware::EventFlag::deleteEventFlag(&efGroup);
+    ASSERT_EQ(android::NO_ERROR, status);
+}
+
+/*
+ * Test FMQ write and read with event flag wait.
+ */
+TYPED_TEST(BlockingReadWrites, FmqWriteAndReadWithShortEventFlagWaitTest) {
+    android::hardware::EventFlag* efGroup = nullptr;
+    android::status_t status = android::hardware::EventFlag::createEventFlag(&this->mFw, &efGroup);
+    ASSERT_EQ(android::NO_ERROR, status);
+    ASSERT_NE(nullptr, efGroup);
+
+    /*
+     * After waiting for some time write into the FMQ
+     * and call Wake on kFmqNotEmpty.
+     */
+    const size_t dataLen = 16;
+    uint8_t dataW[dataLen] = {0};
+    uint8_t dataR[dataLen] = {0};
+    ASSERT_TRUE(this->mQueue->write(dataW, dataLen));
+    status = efGroup->wake(kFmqNotEmpty);
+    ASSERT_EQ(android::NO_ERROR, status);
+
+    ASSERT_TRUE(this->mQueue->readBlocking(dataR, dataLen, static_cast<uint32_t>(kFmqNotEmpty),
+                                           static_cast<uint32_t>(kFmqNotFull), 1 /* timeOutNanos */,
+                                           efGroup));
+    ASSERT_EQ(0, memcmp(dataW, dataR, dataLen));
+
+    status = android::hardware::EventFlag::deleteEventFlag(&efGroup);
+    ASSERT_EQ(android::NO_ERROR, status);
+}
+
+/*
  * Test that odd queue sizes do not cause unaligned error
  * on access to EventFlag object.
  */