From 168fe13784e92cc4dd5a08f21be06f4a9bd1a87f Mon Sep 17 00:00:00 2001
From: Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>
Date: Tue, 6 Sep 2016 10:23:11 -0400
Subject: [PATCH] tls: remove unneeded atomic load
TlsSession state holder 'state_' is loaded twice
when we check for its modification in the TlsSession
state machine code.
std::atomic_compare_exchange_strong returns false when
'state_' is not equals to 'old_state' and in this case
'old_state' is changed for the current value of 'state_'.
So reload it right after the returns is not efficient
and may also have an unexpected corner case.
This patch re-uses the value of 'old_state' for next
processing.
Change-Id: Ia29abc0f5834caabf12f1ae528ff11b132bd603c
Reviewed-by: Stepan Salenikovich <stepan.salenikovich@savoirfairelinux.com>
---
src/security/tls_session.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/security/tls_session.cpp b/src/security/tls_session.cpp
index 75976f0bf9..09641e8e9b 100644
--- a/src/security/tls_session.cpp
+++ b/src/security/tls_session.cpp
@@ -778,7 +778,7 @@ TlsSession::process()
// update state_ with taking care for external state change
if (not std::atomic_compare_exchange_strong(&state_, &old_state, new_state))
- new_state = state_;
+ new_state = old_state;
if (old_state != new_state and callbacks_.onStateChange)
callbacks_.onStateChange(new_state);
--
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