commit 0449b0fa3e3e88da8622da6e95a7eefea8c46a70
author Lloyd Pique <lpique@google.com> Thu Dec 20 16:23:45 2018 -0800
committer Lloyd Pique <lpique@google.com> Mon Jan 07 13:39:45 2019 -0800
tree 57eac962d959508de399454604076cd343d36f66
parent f2c793939c42ff233ced4095cf85bb93ec74523f

Revert "SurfaceFlinger: protect state members in Layer"

State update transactions must be atomic. The fine-grained lock on each
Layer implied otherwise. Revert the fine grained lock as being
unhelpful.

Unfortunately there does not seem to be a way to use Clang thread
annotations to specify the desired locking behavior.

Note that the parent CL addresses the locking problem that led to the
bug.

This reverts commit 83729883eecd31a9907bc79bc21998a90f17105c.

Bug: 119481871
Test: SurfaceFlinger unit tests
Test: go/wm-smoke
Change-Id: I361741f8d10102aeb57f164c847c6063ff93dd14

services/surfaceflinger/LayerVector.cpp

diff --git a/services/surfaceflinger/LayerVector.cpp b/services/surfaceflinger/LayerVector.cpp
index a7db23e..8494524 100644
--- a/services/surfaceflinger/LayerVector.cpp
+++ b/services/surfaceflinger/LayerVector.cpp
@@ -38,12 +38,18 @@
     const auto& l = *reinterpret_cast<const sp<Layer>*>(lhs);
     const auto& r = *reinterpret_cast<const sp<Layer>*>(rhs);
 
-    const auto& [ls, lz] = l->getLayerStackAndZ(mStateSet);
-    const auto& [rs, rz] = r->getLayerStackAndZ(mStateSet);
+    const auto& lState =
+            (mStateSet == StateSet::Current) ? l->getCurrentState() : l->getDrawingState();
+    const auto& rState =
+            (mStateSet == StateSet::Current) ? r->getCurrentState() : r->getDrawingState();
 
+    uint32_t ls = lState.layerStack;
+    uint32_t rs = rState.layerStack;
     if (ls != rs)
         return (ls > rs) ? 1 : -1;
 
+    int32_t lz = lState.z;
+    int32_t rz = rState.z;
     if (lz != rz)
         return (lz > rz) ? 1 : -1;
 
@@ -56,8 +62,9 @@
 void LayerVector::traverseInZOrder(StateSet stateSet, const Visitor& visitor) const {
     for (size_t i = 0; i < size(); i++) {
         const auto& layer = (*this)[i];
-        auto zOrderRelativeOf = layer->getZOrderRelativeOf(stateSet);
-        if (zOrderRelativeOf != nullptr) {
+        auto& state = (stateSet == StateSet::Current) ? layer->getCurrentState()
+                                                      : layer->getDrawingState();
+        if (state.zOrderRelativeOf != nullptr) {
             continue;
         }
         layer->traverseInZOrder(stateSet, visitor);
@@ -67,8 +74,9 @@
 void LayerVector::traverseInReverseZOrder(StateSet stateSet, const Visitor& visitor) const {
     for (auto i = static_cast<int64_t>(size()) - 1; i >= 0; i--) {
         const auto& layer = (*this)[i];
-        auto zOrderRelativeOf = layer->getZOrderRelativeOf(stateSet);
-        if (zOrderRelativeOf != nullptr) {
+        auto& state = (stateSet == StateSet::Current) ? layer->getCurrentState()
+                                                      : layer->getDrawingState();
+        if (state.zOrderRelativeOf != nullptr) {
             continue;
         }
         layer->traverseInReverseZOrder(stateSet, visitor);