Bug-fix: guarantee atomicity for FOP and GACC.
FOP, CAS and GACC are atomic "read-modify-write" operations, which means when the target window is defined on a SHM region, we need inter-process lock to guarantee the atomicity of the entire "read+OP". The current implementation is correct for SHM-based RMA operations, but not correct for AM-based RMA operations: for SHM-based operations, it protects the entire "read+OP", but for AM-based operations, it only protects the "OP" part. This patch fixes this issue by protecting the memory copy to temporary buffer and computation together for AM-based operations. Fix ticket 2226 Signed-off-by: Pavan Balaji <email@example.com>