hash: Make HSH_Fail() rush the waiting list

If the fetch task failed before reaching HSH_Unbusy() we make sure to
signal the waiting list immediately and not wait for the final objcore
reference to be dropped.

The OC_F_FAILED flag will prevent it from being looked up, so there is
no reason to delay the rush.

bin/varnishd/cache/cache_fetch.c

@@ -1043,9 +1043,8 @@ vbf_stp_fail(struct worker *wrk, struct busyobj *bo)
 	CHECK_OBJ_NOTNULL(oc, OBJCORE_MAGIC);
 
 	assert(oc->boc->state < BOS_FINISHED);
-	HSH_Fail(oc);
-	if (!(oc->flags & OC_F_BUSY))
-		HSH_Kill(oc);
+	HSH_Fail(wrk, oc);
+	HSH_Kill(oc);
 	ObjSetState(wrk, oc, BOS_FAILED);
 	return (F_STP_DONE);
 }

bin/varnishd/cache/cache_hash.c

@@ -838,13 +838,16 @@ HSH_Purge(struct worker *wrk, struct objhead *oh, vtim_real ttl_now,
  */
 
 void
-HSH_Fail(struct objcore *oc)
+HSH_Fail(struct worker *wrk, struct objcore *oc)
 {
 	struct objhead *oh;
+	struct rush rush;
 
+	CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
 	CHECK_OBJ_NOTNULL(oc, OBJCORE_MAGIC);
 	oh = oc->objhead;
 	CHECK_OBJ(oh, OBJHEAD_MAGIC);
+	INIT_OBJ(&rush, RUSH_MAGIC);
 
 	/*
 	 * We have to have either a busy bit, so that HSH_Lookup
@@ -854,8 +857,13 @@ HSH_Fail(struct objcore *oc)
 	assert((oc->flags & OC_F_BUSY) || (oc->stobj->stevedore != NULL));
 
 	Lck_Lock(&oh->mtx);
+	if (oc->flags & OC_F_BUSY) {
+		oc->flags &= ~OC_F_BUSY;
+		hsh_rush1(wrk, oc, &rush);
+	}
 	oc->flags |= OC_F_FAILED;
 	Lck_Unlock(&oh->mtx);
+	hsh_rush2(wrk, &rush);
 }
 
 /*---------------------------------------------------------------------

bin/varnishd/cache/cache_objhead.h

@@ -67,11 +67,11 @@ enum lookup_e {
 	HSH_BUSY,
 };
 
-void HSH_Fail(struct objcore *);
 void HSH_Kill(struct objcore *);
 void HSH_Insert(struct worker *, const void *hash, struct objcore *,
     struct ban *);
 void HSH_Unbusy(struct worker *, struct objcore *);
+void HSH_Fail(struct worker *, struct objcore *);
 int HSH_Snipe(const struct worker *, struct objcore *);
 struct boc *HSH_RefBoc(const struct objcore *);
 void HSH_DerefBoc(struct worker *wrk, struct objcore *);