Commit d9cda90a authored Jun 20, 2017 by Daichi Hirono

Add volatile to temporary variable.

FuseBuffer::HandleNotImpl save the value of |request.header.unique| to the
temporary variable, clear the buffer which is a union of |request| and
|response|, then write back the unique value to response.header.unique.

Before the CL, the temporary variable was wrongly removed by the compiler
optimization, and response.header.unique was always 0. The CL adds
volatile modifier as workaround to prevent the compiler optimization
from removing the temporary value.

Bug: 62429763
Test: libappfuse_tests
Change-Id: Ia853f805633f646f316f585a35c7b018000b6eb3
(cherry picked from commit a6dee5e2)

parent 1d873b35

libappfuse/FuseBuffer.cc

+3 −1

Original line number	Diff line number	Diff line
		@@ -251,7 +251,9 @@ void FuseBuffer::HandleInit() {
		void FuseBuffer::HandleNotImpl() {
		LOG(VERBOSE) << "NOTIMPL op=" << request.header.opcode << " uniq="
		<< request.header.unique << " nid=" << request.header.nodeid;
		const uint64_t unique = request.header.unique;
		// Add volatile as a workaround for compiler issue which removes the temporary
		// variable.
		const volatile uint64_t unique = request.header.unique;
		response.Reset(0, -ENOSYS, unique);
		}