From 4c33818dde702128be13040f9fc8bd0a5b835c76 Mon Sep 17 00:00:00 2001
From: Chris Robinson <chris.kcat@gmail.com>
Date: Wed, 21 Dec 2016 19:58:03 -0800
Subject: Avoid duplicating code using a macro

---
 Alc/ALu.c | 41 +++--------------------------------------
 1 file changed, 3 insertions(+), 38 deletions(-)

(limited to 'Alc')

diff --git a/Alc/ALu.c b/Alc/ALu.c
index db032057..dc979522 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -239,7 +239,6 @@ static ALboolean CalcListenerParams(ALCcontext *Context)
 {
     ALlistener *Listener = Context->Listener;
     ALfloat N[3], V[3], U[3], P[3];
-    struct ALlistenerProps *first;
     struct ALlistenerProps *props;
     aluVector vel;
 
@@ -288,24 +287,12 @@ static ALboolean CalcListenerParams(ALCcontext *Context)
     Listener->Params.SourceDistanceModel = ATOMIC_LOAD(&props->SourceDistanceModel, almemory_order_relaxed);
     Listener->Params.DistanceModel = ATOMIC_LOAD(&props->DistanceModel, almemory_order_relaxed);
 
-    /* WARNING: A livelock is theoretically possible if another thread keeps
-     * changing the freelist head without giving this a chance to actually swap
-     * in the old container (practically impossible with this little code,
-     * but...).
-     */
-    first = ATOMIC_LOAD(&Listener->FreeList, almemory_order_acquire);
-    do {
-        ATOMIC_STORE(&props->next, first, almemory_order_relaxed);
-    } while(ATOMIC_COMPARE_EXCHANGE_WEAK(struct ALlistenerProps*,
-            &Listener->FreeList, &first, props, almemory_order_acq_rel,
-            almemory_order_acquire) == 0);
-
+    ATOMIC_REPLACE_HEAD(struct ALlistenerProps*, &Listener->FreeList, props);
     return AL_TRUE;
 }
 
 static ALboolean CalcEffectSlotParams(ALeffectslot *slot, ALCdevice *device)
 {
-    struct ALeffectslotProps *first;
     struct ALeffectslotProps *props;
     ALeffectState *state;
 
@@ -337,18 +324,7 @@ static ALboolean CalcEffectSlotParams(ALeffectslot *slot, ALCdevice *device)
 
     V(state,update)(device, slot, &props->Props);
 
-    /* WARNING: A livelock is theoretically possible if another thread keeps
-     * changing the freelist head without giving this a chance to actually swap
-     * in the old container (practically impossible with this little code,
-     * but...).
-     */
-    first = ATOMIC_LOAD(&slot->FreeList, almemory_order_acquire);
-    do {
-        ATOMIC_STORE(&props->next, first, almemory_order_relaxed);
-    } while(ATOMIC_COMPARE_EXCHANGE_WEAK(struct ALeffectslotProps*,
-            &slot->FreeList, &first, props, almemory_order_acq_rel,
-            almemory_order_acquire) == 0);
-
+    ATOMIC_REPLACE_HEAD(struct ALeffectslotProps*, &slot->FreeList, props);
     return AL_TRUE;
 }
 
@@ -1301,7 +1277,6 @@ static void CalcSourceParams(ALvoice *voice, ALCcontext *context, ALboolean forc
 {
     ALsource *source = voice->Source;
     const ALbufferlistitem *BufferListItem;
-    struct ALsourceProps *first;
     struct ALsourceProps *props;
 
     props = ATOMIC_EXCHANGE(struct ALsourceProps*, &source->Update, NULL, almemory_order_acq_rel);
@@ -1311,17 +1286,7 @@ static void CalcSourceParams(ALvoice *voice, ALCcontext *context, ALboolean forc
     {
         voice->Props = *props;
 
-        /* WARNING: A livelock is theoretically possible if another thread
-         * keeps changing the freelist head without giving this a chance to
-         * actually swap in the old container (practically impossible with this
-         * little code, but...).
-         */
-        first = ATOMIC_LOAD(&source->FreeList, almemory_order_acquire);
-        do {
-            ATOMIC_STORE(&props->next, first, almemory_order_relaxed);
-        } while(ATOMIC_COMPARE_EXCHANGE_WEAK(struct ALsourceProps*,
-                &source->FreeList, &first, props, almemory_order_acq_rel,
-                almemory_order_acquire) == 0);
+        ATOMIC_REPLACE_HEAD(struct ALsourceProps*, &source->FreeList, props);
     }
 
     BufferListItem = ATOMIC_LOAD(&source->queue, almemory_order_relaxed);
-- 
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