Simplify HSH_Lookup 3/N

Use req->hash_always_miss directly

Inspired by:    #2856

bin/varnishd/cache/cache_hash.c

@@ -338,8 +338,7 @@ hsh_insert_busyobj(struct worker *wrk, struct objhead *oh)
  */
 
 enum lookup_e
-HSH_Lookup(struct req *req, struct objcore **ocp, struct objcore **bocp,
-    int always_insert)
+HSH_Lookup(struct req *req, struct objcore **ocp, struct objcore **bocp)
 {
 	struct worker *wrk;
 	struct objhead *oh;
@@ -384,7 +383,7 @@ HSH_Lookup(struct req *req, struct objcore **ocp, struct objcore **bocp,
 	CHECK_OBJ_NOTNULL(oh, OBJHEAD_MAGIC);
 	Lck_AssertHeld(&oh->mtx);
 
-	if (always_insert) {
+	if (req->hash_always_miss) {
 		/* XXX: should we do predictive Vary in this case ? */
 		/* Insert new objcore in objecthead and release mutex */
 		*bocp = hsh_insert_busyobj(wrk, oh);
@@ -472,7 +471,7 @@ HSH_Lookup(struct req *req, struct objcore **ocp, struct objcore **bocp,
 			wrk->stats->cache_hitmiss++;
 			VSLb(req->vsl, SLT_HitMiss, "%u %.6f", xid, dttl);
 			return (HSH_HITMISS);
-		} 
+		}
 		if (oc->hits < LONG_MAX)
 			oc->hits++;
 		AN(hsh_deref_objhead_unlock(wrk, &oh));

bin/varnishd/cache/cache_objhead.h

@@ -68,8 +68,7 @@ int HSH_DerefObjCore(struct worker *, struct objcore **, int rushmax);
 #define HSH_RUSH_POLICY -1
 #define HSH_RUSH_ALL	INT_MAX
 
-enum lookup_e HSH_Lookup(struct req *, struct objcore **, struct objcore **,
-    int always_insert);
+enum lookup_e HSH_Lookup(struct req *, struct objcore **, struct objcore **);
 void HSH_Ref(struct objcore *o);
 void HSH_AddString(struct req *, void *ctx, const char *str);
 unsigned HSH_Purge(struct worker *, struct objhead *, vtim_real ttl_now,

bin/varnishd/cache/cache_req_fsm.c

@@ -495,7 +495,7 @@ cnt_lookup(struct worker *wrk, struct req *req)
 	AZ(req->objcore);
 	if (req->hash_objhead)
 		had_objhead = 1;
-	lr = HSH_Lookup(req, &oc, &busy, req->hash_always_miss ? 1 : 0);
+	lr = HSH_Lookup(req, &oc, &busy);
 	if (lr == HSH_BUSY) {
 		/*
 		 * We lost the session to a busy object, disembark the
@@ -986,7 +986,8 @@ cnt_purge(struct worker *wrk, struct req *req)
 	VRY_Prep(req);
 
 	AZ(req->objcore);
-	lr = HSH_Lookup(req, &oc, &boc, 1);
+	req->hash_always_miss = 1;
+	lr = HSH_Lookup(req, &oc, &boc);
 	assert (lr == HSH_MISS);
 	AZ(oc);
 	CHECK_OBJ_NOTNULL(boc, OBJCORE_MAGIC);