Always unmap in VSM_Unmap when refs reaches zero.

Remove the unmap-handling from vsm_refresh_set.

Revert bdd70290 "Always munmap(2) segments when we delete them."

lib/libvarnishapi/vsm.c

@@ -299,26 +299,6 @@ VSM_ResetError(struct vsm *vd)
 	VSB_destroy(&vd->diag);
 }
 
-/*--------------------------------------------------------------------
- */
-
-static void
-vsm_unmap(struct vsm_seg *vg)
-{
-	size_t sz, ps, len;
-
-	CHECK_OBJ_NOTNULL(vg, VSM_SEG_MAGIC);
-	AN(vg->b);
-	AN(vg->e);
-	sz = strtoul(vg->av[2], NULL, 10);
-	assert(sz > 0);
-	ps = getpagesize();
-	len = RUP2(sz, ps);
-	AZ(munmap(vg->b, len));
-	vg->b = NULL;
-	vg->e = NULL;
-}
-
 /*--------------------------------------------------------------------
  */
 
@@ -490,8 +470,6 @@ vsm_refresh_set(struct vsm *vd, struct vsm_set *vs, struct vsb *vsb)
 				vg->stale = 1;
 				VTAILQ_INSERT_TAIL(&vs->stale, vg, list);
 			} else {
-				if (vg->b != NULL)
-					vsm_unmap(vg);
 				VAV_Free(vg->av);
 				FREE_OBJ(vg);
 			}
@@ -724,6 +702,7 @@ int
 VSM_Unmap(struct vsm *vd, struct vsm_fantom *vf)
 {
 	struct vsm_seg *vg;
+	size_t sz, ps, len;
 
 	CHECK_OBJ_NOTNULL(vd, VSM_MAGIC);
 	AN(vd->attached);
@@ -738,12 +717,18 @@ VSM_Unmap(struct vsm *vd, struct vsm_fantom *vf)
 	vf->e = NULL;
 	if (vg->refs > 0)
 		return(0);
+	AN(vg->b);
+	AN(vg->e);
+	sz = strtoul(vg->av[2], NULL, 10);
+	assert(sz > 0);
+	ps = getpagesize();
+	len = RUP2(sz, ps);
+	AZ(munmap(vg->b, len));
+	vg->b = vg->e = NULL;
 	if (vg->stale) {
 		VTAILQ_REMOVE(&vg->set->stale, vg, list);
 		VAV_Free(vg->av);
 		FREE_OBJ(vg);
-	} else {
-		vsm_unmap(vg);
 	}
 	return (0);
 }