diff --git a/media/codec2/vndk/C2AllocatorBlob.cpp b/media/codec2/vndk/C2AllocatorBlob.cpp
index 50c9e59..aa05499 100644
--- a/media/codec2/vndk/C2AllocatorBlob.cpp
+++ b/media/codec2/vndk/C2AllocatorBlob.cpp
@@ -17,6 +17,8 @@
 // #define LOG_NDEBUG 0
 #define LOG_TAG "C2AllocatorBlob"
 
+#include <set>
+
 #include <C2AllocatorBlob.h>
 #include <C2PlatformSupport.h>
 
@@ -67,6 +69,10 @@
 private:
     const std::shared_ptr<C2GraphicAllocation> mGraphicAllocation;
     const C2Allocator::id_t mAllocatorId;
+
+    std::mutex mMapLock;
+    std::multiset<std::pair<size_t, size_t>> mMappedOffsetSize;
+    uint8_t *mMappedAddr;
 };
 
 C2AllocationBlob::C2AllocationBlob(
@@ -74,20 +80,74 @@
         C2Allocator::id_t allocatorId)
       : C2LinearAllocation(capacity),
         mGraphicAllocation(std::move(graphicAllocation)),
-        mAllocatorId(allocatorId) {}
+        mAllocatorId(allocatorId),
+        mMappedAddr(nullptr) {}
 
-C2AllocationBlob::~C2AllocationBlob() {}
+C2AllocationBlob::~C2AllocationBlob() {
+    if (mMappedAddr) {
+        C2Rect rect(capacity(), kLinearBufferHeight);
+        mGraphicAllocation->unmap(&mMappedAddr, rect, nullptr);
+    }
+}
 
 c2_status_t C2AllocationBlob::map(size_t offset, size_t size, C2MemoryUsage usage,
                                   C2Fence* fence, void** addr /* nonnull */) {
+    *addr = nullptr;
+    if (size > capacity() || offset > capacity() || offset > capacity() - size) {
+        ALOGV("C2AllocationBlob: map: bad offset / size: offset=%zu size=%zu capacity=%u",
+                offset, size, capacity());
+        return C2_BAD_VALUE;
+    }
+    std::unique_lock<std::mutex> lock(mMapLock);
+    if (mMappedAddr) {
+        *addr = mMappedAddr + offset;
+        mMappedOffsetSize.insert({offset, size});
+        ALOGV("C2AllocationBlob: mapped from existing mapping: offset=%zu size=%zu capacity=%u",
+                offset, size, capacity());
+        return C2_OK;
+    }
     C2PlanarLayout layout;
-    C2Rect rect = C2Rect(size, kLinearBufferHeight).at(offset, 0u);
-    return mGraphicAllocation->map(rect, usage, fence, &layout, reinterpret_cast<uint8_t**>(addr));
+    C2Rect rect = C2Rect(capacity(), kLinearBufferHeight);
+    c2_status_t err = mGraphicAllocation->map(rect, usage, fence, &layout, &mMappedAddr);
+    if (err != C2_OK) {
+        ALOGV("C2AllocationBlob: map failed: offset=%zu size=%zu capacity=%u err=%d",
+                offset, size, capacity(), err);
+        mMappedAddr = nullptr;
+        return err;
+    }
+    *addr = mMappedAddr + offset;
+    mMappedOffsetSize.insert({offset, size});
+    ALOGV("C2AllocationBlob: new map succeeded: offset=%zu size=%zu capacity=%u",
+            offset, size, capacity());
+    return C2_OK;
 }
 
 c2_status_t C2AllocationBlob::unmap(void* addr, size_t size, C2Fence* fenceFd) {
-    C2Rect rect(size, kLinearBufferHeight);
-    return mGraphicAllocation->unmap(reinterpret_cast<uint8_t**>(&addr), rect, fenceFd);
+    std::unique_lock<std::mutex> lock(mMapLock);
+    uint8_t *u8Addr = static_cast<uint8_t *>(addr);
+    if (u8Addr < mMappedAddr || mMappedAddr + capacity() < u8Addr + size) {
+        ALOGV("C2AllocationBlob: unmap: Bad addr / size: addr=%p size=%zu capacity=%u",
+                addr, size, capacity());
+        return C2_BAD_VALUE;
+    }
+    auto it = mMappedOffsetSize.find(std::make_pair(u8Addr - mMappedAddr, size));
+    if (it == mMappedOffsetSize.end()) {
+        ALOGV("C2AllocationBlob: unrecognized map: addr=%p size=%zu capacity=%u",
+                addr, size, capacity());
+        return C2_BAD_VALUE;
+    }
+    mMappedOffsetSize.erase(it);
+    if (!mMappedOffsetSize.empty()) {
+        ALOGV("C2AllocationBlob: still maintain mapping: addr=%p size=%zu capacity=%u",
+                addr, size, capacity());
+        return C2_OK;
+    }
+    C2Rect rect(capacity(), kLinearBufferHeight);
+    c2_status_t err = mGraphicAllocation->unmap(&mMappedAddr, rect, fenceFd);
+    ALOGV("C2AllocationBlob: last unmap: addr=%p size=%zu capacity=%u err=%d",
+            addr, size, capacity(), err);
+    mMappedAddr = nullptr;
+    return err;
 }
 
 /* ====================================== BLOB ALLOCATOR ====================================== */