From 429c2f93f4d1ef234debcb81d1b5cc06233a909a Mon Sep 17 00:00:00 2001
From: Peng Huang <penghuang@chromium.org>
Date: Tue, 17 Jan 2023 23:40:41 +0000
Subject: [PATCH] Fix vulkan::Buffer::TransitionUsageAndGetResourceBarrier()

Do not transition if the buffer usage is already MapWrite

Change-Id: I16cf68501e19a5b60d6c6f28eaa539df691f14fd
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/117240
Reviewed-by: Austin Eng <enga@chromium.org>
Auto-Submit: Peng Huang <penghuang@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Peng Huang <penghuang@chromium.org>
---
 src/dawn/native/vulkan/BufferVk.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/dawn/native/vulkan/BufferVk.cpp b/src/dawn/native/vulkan/BufferVk.cpp
index 5bec8da4ac..8e0811cc26 100644
--- a/src/dawn/native/vulkan/BufferVk.cpp
+++ b/src/dawn/native/vulkan/BufferVk.cpp
@@ -262,10 +262,11 @@ bool Buffer::TransitionUsageAndGetResourceBarrier(wgpu::BufferUsage usage,
                                                   VkPipelineStageFlags* srcStages,
                                                   VkPipelineStageFlags* dstStages) {
     bool lastIncludesTarget = IsSubset(usage, mLastUsage);
-    bool lastReadOnly = IsSubset(mLastUsage, kReadOnlyBufferUsages);
+    constexpr wgpu::BufferUsage kReuseNoBarrierBufferUsages =
+        kReadOnlyBufferUsages | wgpu::BufferUsage::MapWrite;
+    bool lastCanBeReusedWithoutBarrier = IsSubset(mLastUsage, kReuseNoBarrierBufferUsages);
 
-    // We can skip transitions to already current read-only usages.
-    if (lastIncludesTarget && lastReadOnly) {
+    if (lastIncludesTarget && lastCanBeReusedWithoutBarrier) {
         return false;
     }