diff --git a/dlls/dsound/primary.c b/dlls/dsound/primary.c
index f5a1020700a..ed41a5c4844 100644
--- a/dlls/dsound/primary.c
+++ b/dlls/dsound/primary.c
@@ -250,18 +250,18 @@ static HRESULT DSOUND_PrimaryOpen(DirectSoundDevice *device, WAVEFORMATEX *wfx,
         }
         FillMemory(newbuf, new_buflen, (wfx->wBitsPerSample == 8) ? 128 : 0);
     } else if (!mixfloat) {
-        DWORD alloc_len = frames * sizeof(float);
+        new_buflen = frames * sizeof(float);
 
         if (device->buffer)
-            newbuf = HeapReAlloc(GetProcessHeap(), 0, device->buffer, alloc_len);
+            newbuf = HeapReAlloc(GetProcessHeap(), 0, device->buffer, new_buflen);
         else
-            newbuf = HeapAlloc(GetProcessHeap(), 0, alloc_len);
+            newbuf = HeapAlloc(GetProcessHeap(), 0, new_buflen);
 
         if (!newbuf) {
             ERR("failed to allocate primary buffer\n");
             return DSERR_OUTOFMEMORY;
         }
-        FillMemory(newbuf, alloc_len, (wfx->wBitsPerSample == 8) ? 128 : 0);
+        FillMemory(newbuf, new_buflen, (wfx->wBitsPerSample == 8) ? 128 : 0);
     } else {
         HeapFree(GetProcessHeap(), 0, device->buffer);
         newbuf = NULL;