gralloc: Attribute buffer ownership to last caller

Switch buffer management from creator to latest registrant

Change-Id: If6b1ab1a553f701e4a1038c089f2b2ecb02c2e8b

exynos4/hal/libgralloc_ump/gralloc_module.cpp

@@ -239,6 +239,8 @@ static int gralloc_register_buffer(gralloc_module_t const* module, buffer_handle
         s_ump_is_open = 1;
     }
 
+    hnd->pid = getpid();
+
     if (hnd->flags & private_handle_t::PRIV_FLAGS_USES_UMP) {
         hnd->ump_mem_handle = (int)ump_handle_create_from_secure_id(hnd->ump_id);
         if (UMP_INVALID_MEMORY_HANDLE != (ump_handle)hnd->ump_mem_handle) {
@@ -318,8 +320,8 @@ static int gralloc_unregister_buffer(gralloc_module_t const* module, buffer_hand
     ALOGE_IF(hnd->lockState & private_handle_t::LOCK_STATE_READ_MASK,
             "[unregister] handle %p still locked (state=%08x)", hnd, hnd->lockState);
 
-    /* never unmap buffers that were created in this process */
-    if (hnd->pid != getpid()) {
+    /* never unmap buffers that were not registered in this process */
+    if (hnd->pid == getpid()) {
         pthread_mutex_lock(&s_map_lock);
         if (hnd->flags & private_handle_t::PRIV_FLAGS_USES_UMP) {
             ump_mapped_pointer_release((ump_handle)hnd->ump_mem_handle);