SQUASHME: ocstash differences to dridis proposal

This is basically a diff to bf84027 and
bf84027 combined

Author: nigoroll

bin/varnishd/cache/cache_req.c

@@ -47,20 +47,22 @@
 #include "vtim.h"
 
 /*--------------------------------------------------------------------
- * TODO: describe.
+ * Facility to keep obcore references until the end of the task across restarts
  */
 
 struct ocstash {
-	unsigned		l;
-	unsigned		n;
+	unsigned		magic;
+#define OCSTASH_MAGIC		0x242031b5
+	uint16_t		l;
+	uint16_t		n;
 	struct objcore *	ocs[] v_counted_by_(l);
 };
 
 static void
 ocstash_push(struct ocstash *stash, struct objcore **ocp)
 {
 
-	AN(stash);
+	CHECK_OBJ_NOTNULL(stash, OCSTASH_MAGIC);
 	assert(stash->n < stash->l);
 	TAKE_OBJ_NOTNULL(stash->ocs[stash->n], ocp, OBJCORE_MAGIC);
 	stash->n++;
@@ -69,10 +71,11 @@ ocstash_push(struct ocstash *stash, struct objcore **ocp)
 static void
 ocstash_clear(struct worker *wrk, struct ocstash *stash)
 {
-	unsigned u;
+	uint16_t u;
 
 	CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
-	AN(stash);
+	CHECK_OBJ_NOTNULL(stash, OCSTASH_MAGIC);
+	assert(stash->n <= stash->l);
 	for (u = 0; u < stash->n; u++)
 		(void)HSH_DerefObjCore(wrk, &stash->ocs[u], HSH_RUSH_POLICY);
 	for (; u < stash->l; u++)
@@ -172,7 +175,7 @@ Req_New(struct sess *sp)
 {
 	struct pool *pp;
 	struct req *req;
-	uint16_t nhttp;
+	uint16_t l, nhttp;
 	unsigned sz, hl;
 	char *p, *e;
 
@@ -232,10 +235,12 @@ Req_New(struct sess *sp)
 	p = (void*)PRNDUP(p + sizeof(*req->top));
 
 	req->max_restarts = cache_param->max_restarts;
-	sz = SIZEOF_FLEX_OBJ(req->stash, ocs, req->max_restarts + 1);
+	assert(req->max_restarts + 1 <= UINT16_MAX);
+	l = req->max_restarts + 1;
+	sz = SIZEOF_FLEX_OBJ(req->stash, ocs, l);
 	req->stash = (void*)p;
-	ZERO_OBJ(req->stash, sz);
-	req->stash->l = req->max_restarts + 1;
+	req->stash->magic = OCSTASH_MAGIC;
+	req->stash->l = l;
 	p += sz;
 	p = (void*)PRNDUP(p);