From 7fa3df33f217c921cad1ef5b67d6ad1c53c5e547 Mon Sep 17 00:00:00 2001
From: Victor Julien <victor@inliniac.net>
Date: Wed, 7 Dec 2011 08:03:10 +0100
Subject: [PATCH] flow engine: introduce FlowRequeueMoveToBot

As part of a clean up of how FlowRequeue is used, introduce
FlowRequeueMoveToBot for moving a flow to the bottom of it's queue.
---
 src/flow-queue.c | 40 ++++++++++++++++++++++++++++++++++++++++
 src/flow-queue.h |  1 +
 src/flow.c       | 10 +++++-----
 3 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/src/flow-queue.c b/src/flow-queue.c
index 77357d1992..9a7a85bb10 100644
--- a/src/flow-queue.c
+++ b/src/flow-queue.c
@@ -172,3 +172,43 @@ void FlowRequeue(Flow *f, FlowQueue *srcq, FlowQueue *dstq, uint8_t need_srclock
     SCMutexUnlock(&dstq->mutex_q);
 }
 
+/**
+ *  \brief Move flow to bottom of queue
+ *
+ *  \param f the flow to be transfered
+ *  \param q the queue
+ */
+void FlowRequeueMoveToBot(Flow *f, FlowQueue *q)
+{
+#ifdef DEBUG
+    BUG_ON(q == NULL || f == NULL);
+#endif /* DEBUG */
+
+    SCMutexLock(&q->mutex_q);
+
+    /* remove from the queue */
+    if (q->top == f)
+        q->top = f->lnext;       /* remove from queue top */
+    if (q->bot == f)
+        q->bot = f->lprev;       /* remove from queue bot */
+    if (f->lprev != NULL)
+        f->lprev->lnext = f->lnext; /* remove from flow prev */
+    if (f->lnext != NULL)
+        f->lnext->lprev = f->lprev; /* remove from flow next */
+
+    /* readd to the queue (append) */
+    f->lprev = q->bot;
+
+    if (f->lprev != NULL)
+        f->lprev->lnext = f;
+
+    f->lnext = NULL;
+
+    q->bot = f;
+
+    if (q->top == NULL)
+        q->top = f;
+
+    SCMutexUnlock(&q->mutex_q);
+}
+
diff --git a/src/flow-queue.h b/src/flow-queue.h
index e4679daa28..76f0b3bac7 100644
--- a/src/flow-queue.h
+++ b/src/flow-queue.h
@@ -48,6 +48,7 @@ void FlowQueueDestroy (FlowQueue *);
 void FlowEnqueue (FlowQueue *, Flow *);
 Flow *FlowDequeue (FlowQueue *);
 void FlowRequeue(Flow *, FlowQueue *, FlowQueue *, uint8_t);
+void FlowRequeueMoveToBot(Flow *, FlowQueue *);
 
 #endif /* __FLOW_QUEUE_H__ */
 
diff --git a/src/flow.c b/src/flow.c
index 800eaf3523..83c87bebf4 100644
--- a/src/flow.c
+++ b/src/flow.c
@@ -112,7 +112,7 @@ void FlowUpdateQueue(Flow *f)
             f->flags |= FLOW_EST_LIST; /* transition */
             f->flags &= ~FLOW_NEW_LIST;
         } else {
-            FlowRequeue(f, &flow_new_q[f->protomap], &flow_new_q[f->protomap], 1);
+            FlowRequeueMoveToBot(f, &flow_new_q[f->protomap]);
         }
     } else if (f->flags & FLOW_EST_LIST) {
         if (flow_proto[f->protomap].GetProtoState != NULL) {
@@ -126,12 +126,12 @@ void FlowUpdateQueue(Flow *f)
             } else {
                 /* Pull and put back -- this way the flows on
                  * top of the list are least recently used. */
-                FlowRequeue(f, &flow_est_q[f->protomap], &flow_est_q[f->protomap], 1);
+                FlowRequeueMoveToBot(f, &flow_est_q[f->protomap]);
             }
         } else {
             /* Pull and put back -- this way the flows on
              * top of the list are least recently used. */
-            FlowRequeue(f, &flow_est_q[f->protomap], &flow_est_q[f->protomap], 1);
+            FlowRequeueMoveToBot(f, &flow_est_q[f->protomap]);
         }
     } else if (f->flags & FLOW_CLOSED_LIST){
         /* for the case of ssn reuse in TCP sessions we need to be able to pull
@@ -148,12 +148,12 @@ void FlowUpdateQueue(Flow *f)
             } else {
                 /* Pull and put back -- this way the flows on
                  * top of the list are least recently used. */
-                FlowRequeue(f, &flow_close_q[f->protomap], &flow_close_q[f->protomap], 1);
+                FlowRequeueMoveToBot(f, &flow_close_q[f->protomap]);
             }
         } else {
             /* Pull and put back -- this way the flows on
              * top of the list are least recently used. */
-            FlowRequeue(f, &flow_close_q[f->protomap], &flow_close_q[f->protomap], 1);
+            FlowRequeueMoveToBot(f, &flow_close_q[f->protomap]);
         }
     }