Merge "Fix potential synchronized race between SF and InputFlinger" into sc-dev (807ae39c) · Commits · e / os / android_frameworks_native

services/surfaceflinger/SurfaceFlinger.cpp

+7 −5

Original line number	Original line	Diff line number	Diff line
	@@ -3105,7 +3105,7 @@ void SurfaceFlinger::setVsyncConfig(const VsyncModulator::VsyncConfig& config,

	void SurfaceFlinger::commitTransaction() {		void SurfaceFlinger::commitTransaction() {
	commitTransactionLocked();		commitTransactionLocked();
	signalSynchronousTransactions();		signalSynchronousTransactions(CountDownLatch::eSyncTransaction);
	mAnimTransactionPending = false;		mAnimTransactionPending = false;
	}		}

	@@ -3527,7 +3527,9 @@ void SurfaceFlinger::queueTransaction(TransactionState& state) {
	// Generate a CountDownLatch pending state if this is a synchronous transaction.		// Generate a CountDownLatch pending state if this is a synchronous transaction.
	if ((state.flags & eSynchronous) \|\| state.inputWindowCommands.syncInputWindows) {		if ((state.flags & eSynchronous) \|\| state.inputWindowCommands.syncInputWindows) {
	state.transactionCommittedSignal = std::make_shared<CountDownLatch>(		state.transactionCommittedSignal = std::make_shared<CountDownLatch>(
	(state.inputWindowCommands.syncInputWindows ? 2 : 1));		(state.inputWindowCommands.syncInputWindows
			? (CountDownLatch::eSyncInputWindows \| CountDownLatch::eSyncTransaction)
			: CountDownLatch::eSyncTransaction));
	}		}

	mTransactionQueue.emplace(state);		mTransactionQueue.emplace(state);
	@@ -3552,10 +3554,10 @@ void SurfaceFlinger::waitForSynchronousTransaction(
	}		}
	}		}

	void SurfaceFlinger::signalSynchronousTransactions() {		void SurfaceFlinger::signalSynchronousTransactions(const uint32_t flag) {
	for (auto it = mTransactionCommittedSignals.begin();		for (auto it = mTransactionCommittedSignals.begin();
	it != mTransactionCommittedSignals.end();) {		it != mTransactionCommittedSignals.end();) {
	if ((*it)->countDown() == 0) {		if ((*it)->countDown(flag)) {
	it = mTransactionCommittedSignals.erase(it);		it = mTransactionCommittedSignals.erase(it);
	} else {		} else {
	it++;		it++;
	@@ -6175,7 +6177,7 @@ status_t SurfaceFlinger::renderScreenImplLocked(

	void SurfaceFlinger::setInputWindowsFinished() {		void SurfaceFlinger::setInputWindowsFinished() {
	Mutex::Autolock _l(mStateLock);		Mutex::Autolock _l(mStateLock);
	signalSynchronousTransactions();		signalSynchronousTransactions(CountDownLatch::eSyncInputWindows);
	}		}

	// ---------------------------------------------------------------------------		// ---------------------------------------------------------------------------

services/surfaceflinger/SurfaceFlinger.h

+17 −10

Original line number	Original line	Diff line number	Diff line
	@@ -467,24 +467,31 @@ private:

	class CountDownLatch {		class CountDownLatch {
	public:		public:
	explicit CountDownLatch(int32_t count) : mCount(count) {}		enum {
			eSyncTransaction = 1 << 0,
			eSyncInputWindows = 1 << 1,
			};
			explicit CountDownLatch(uint32_t flags) : mFlags(flags) {}

	int32_t countDown() {		// True if there is no waiting condition after count down.
			bool countDown(uint32_t flag) {
	std::unique_lock<std::mutex> lock(mMutex);		std::unique_lock<std::mutex> lock(mMutex);
	if (mCount == 0) {		if (mFlags == 0) {
	return 0;		return true;
	}		}
	if (--mCount == 0) {		mFlags &= ~flag;
			if (mFlags == 0) {
	mCountDownComplete.notify_all();		mCountDownComplete.notify_all();
			return true;
	}		}
	return mCount;		return false;
	}		}

	// Return true if triggered.		// Return true if triggered.
	bool wait_until(const std::chrono::seconds& timeout) const {		bool wait_until(const std::chrono::seconds& timeout) const {
	std::unique_lock<std::mutex> lock(mMutex);		std::unique_lock<std::mutex> lock(mMutex);
	const auto untilTime = std::chrono::system_clock::now() + timeout;		const auto untilTime = std::chrono::system_clock::now() + timeout;
	while (mCount != 0) {		while (mFlags != 0) {
	// Conditional variables can be woken up sporadically, so we check count		// Conditional variables can be woken up sporadically, so we check count
	// to verify the wakeup was triggered by \|countDown\|.		// to verify the wakeup was triggered by \|countDown\|.
	if (std::cv_status::timeout == mCountDownComplete.wait_until(lock, untilTime)) {		if (std::cv_status::timeout == mCountDownComplete.wait_until(lock, untilTime)) {
	@@ -495,7 +502,7 @@ private:
	}		}

	private:		private:
	int32_t mCount;		uint32_t mFlags;
	mutable std::condition_variable mCountDownComplete;		mutable std::condition_variable mCountDownComplete;
	mutable std::mutex mMutex;		mutable std::mutex mMutex;
	};		};
	@@ -1124,7 +1131,7 @@ private:
	// Add transaction to the Transaction Queue		// Add transaction to the Transaction Queue
	void queueTransaction(TransactionState& state) EXCLUDES(mQueueLock);		void queueTransaction(TransactionState& state) EXCLUDES(mQueueLock);
	void waitForSynchronousTransaction(const CountDownLatch& transactionCommittedSignal);		void waitForSynchronousTransaction(const CountDownLatch& transactionCommittedSignal);
	void signalSynchronousTransactions();		void signalSynchronousTransactions(const uint32_t flag);

	/*		/*
	* Generic Layer Metadata		* Generic Layer Metadata