Revert "Do not unmap twice a mapping."

This reverts commit a303efff1731e5b7e9574a4e54701515a4c16d41.

Reason for revert: b/368661421, triggers a CHECK in `eng` builds

Change-Id: I18b5d87ac6ab5526f24af4daa47c1cf09a33d1b5

2 files changed, 9 insertions, 26 deletions

diff --git a/libartbase/base/mem_map.h b/libartbase/base/mem_map.h
index 4b4a56a23f..a3af44fadb 100644
--- a/libartbase/base/mem_map.h
+++ b/libartbase/base/mem_map.h
@@ -220,28 +220,6 @@ class MemMap {
                             error_msg);
   }
 
-  static MemMap MapFile(size_t byte_count,
-                        int prot,
-                        int flags,
-                        int fd,
-                        off_t start,
-                        bool low_4gb,
-                        const char* filename,
-                        bool reuse,
-                        std::string* error_msg) {
-    return MapFileAtAddress(nullptr,
-                            byte_count,
-                            prot,
-                            flags,
-                            fd,
-                            start,
-                            /*low_4gb=*/ low_4gb,
-                            filename,
-                            reuse,
-                            /*reservation=*/ nullptr,
-                            error_msg);
-  }
-
   // Map part of a file, taking care of non-page aligned offsets. The "start" offset is absolute,
   // not relative. This version allows requesting a specific address for the base of the mapping.
   //
@@ -447,8 +425,8 @@ class MemMap {
   size_t base_size_ = 0u;       // Length of mapping. May be changed by RemapAtEnd (ie Zygote).
   int prot_ = 0;                // Protection of the map.
 
-  // When reuse_ is true, this is a view of a mapping on which
-  // we do not take ownership and are not responsible for
+  // When reuse_ is true, this is just a view of an existing mapping
+  // and we do not take ownership and are not responsible for
   // unmapping.
   bool reuse_ = false;
 
diff --git a/runtime/jit/jit.cc b/runtime/jit/jit.cc
index bdfb911003..567f07adf0 100644
--- a/runtime/jit/jit.cc
+++ b/runtime/jit/jit.cc
@@ -568,7 +568,6 @@ void Jit::NotifyZygoteCompilationDone() {
       /* start= */ 0,
       /* low_4gb= */ false,
       "boot-image-methods",
-      /* reuse= */ true,  // The mapping will be reused by the mremaps below.
       &error_str);
 
   if (!child_mapping_methods.IsValid()) {
@@ -641,6 +640,10 @@ void Jit::NotifyZygoteCompilationDone() {
   // Mark that compilation of boot classpath is done, and memory can now be
   // shared. Other processes will pick up this information.
   code_cache_->GetZygoteMap()->SetCompilationState(ZygoteCompilationState::kNotifiedOk);
+
+  // The private mapping created for this process has been mremaped. We can
+  // reset it.
+  child_mapping_methods.Reset();
 }
 
 class JitCompileTask final : public Task {
@@ -972,7 +975,6 @@ void Jit::MapBootImageMethods() {
       /* start= */ 0,
       /* low_4gb= */ false,
       "boot-image-methods",
-      /* reuse= */ true,  // The mapping will be reused by the mremaps below.
       &error_str);
 
   // We don't need the fd anymore.
@@ -1069,6 +1071,9 @@ void Jit::MapBootImageMethods() {
     offset += capacity;
   }
 
+  // The private mapping created for this process has been mremaped. We can
+  // reset it.
+  child_mapping_methods.Reset();
   LOG(INFO) << "Successfully mapped boot image methods";
 }