folly/IndexedMemPool: correct an erroneous test for failed mmap

Summary:
* folly/IndexedMemPool.h (IndexedMemPool): Correct the test for
failed mmap.  Upon failure, it returns MAP_FAILED, not nullptr.

Test Plan:
fbconfig -r folly/test:indexed_mem_pool_test && fbmake runtests

Reviewed By: ngbronson@fb.com

FB internal diff: D1480389

Tasks: 4846893
@override-unit-failures

diff --git a/folly/IndexedMemPool.h b/folly/IndexedMemPool.h
index a668627ed817ee54562585a84ba9d3b36cd967a7..d03c35c65cc574a3a80ef7375de61324d8cbb58a 100644 (file)
--- a/folly/IndexedMemPool.h
+++ b/folly/IndexedMemPool.h
@@ -121,7 +121,7 @@ struct IndexedMemPool : boost::noncopyable {
     slots_ = static_cast<Slot*>(mmap(nullptr, mmapLength_,
                                      PROT_READ | PROT_WRITE,
                                      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0));
-    if (slots_ == nullptr) {
+    if (slots_ == MAP_FAILED) {
       assert(errno == ENOMEM);
       throw std::bad_alloc();
     }