caif: Bugfix - use standard Linux lists

Discovered bug when running high number of parallel connect requests.
Replace buggy home brewed list with linux/list.h.
Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/caif/cfctrl.h

@@ -94,8 +94,8 @@ struct cfctrl_request_info {
 	enum cfctrl_cmd cmd;
 	u8 channel_id;
 	struct cfctrl_link_param param;
-	struct cfctrl_request_info *next;
 	struct cflayer *client_layer;
+	struct list_head list;
 };
 
 struct cfctrl {
@@ -103,7 +103,7 @@ struct cfctrl {
 	struct cfctrl_rsp res;
 	atomic_t req_seq_no;
 	atomic_t rsp_seq_no;
-	struct cfctrl_request_info *first_req;
+	struct list_head list;
 	/* Protects from simultaneous access to first_req list */
 	spinlock_t info_list_lock;
 #ifndef CAIF_NO_LOOP

net/caif/cfctrl.c

@@ -44,13 +44,14 @@ struct cflayer *cfctrl_create(void)
 	dev_info.id = 0xff;
 	memset(this, 0, sizeof(*this));
 	cfsrvl_init(&this->serv, 0, &dev_info);
-	spin_lock_init(&this->info_list_lock);
 	atomic_set(&this->req_seq_no, 1);
 	atomic_set(&this->rsp_seq_no, 1);
 	this->serv.layer.receive = cfctrl_recv;
 	sprintf(this->serv.layer.name, "ctrl");
 	this->serv.layer.ctrlcmd = cfctrl_ctrlcmd;
 	spin_lock_init(&this->loop_linkid_lock);
+	spin_lock_init(&this->info_list_lock);
+	INIT_LIST_HEAD(&this->list);
 	this->loop_linkid = 1;
 	return &this->serv.layer;
 }
@@ -112,20 +113,10 @@ bool cfctrl_req_eq(struct cfctrl_request_info *r1,
 void cfctrl_insert_req(struct cfctrl *ctrl,
 			      struct cfctrl_request_info *req)
 {
-	struct cfctrl_request_info *p;
 	spin_lock(&ctrl->info_list_lock);
-	req->next = NULL;
 	atomic_inc(&ctrl->req_seq_no);
 	req->sequence_no = atomic_read(&ctrl->req_seq_no);
-	if (ctrl->first_req == NULL) {
-		ctrl->first_req = req;
-		spin_unlock(&ctrl->info_list_lock);
-		return;
-	}
-	p = ctrl->first_req;
-	while (p->next != NULL)
-		p = p->next;
-	p->next = req;
+	list_add_tail(&req->list, &ctrl->list);
 	spin_unlock(&ctrl->info_list_lock);
 }
 
@@ -133,46 +124,28 @@ void cfctrl_insert_req(struct cfctrl *ctrl,
 struct cfctrl_request_info *cfctrl_remove_req(struct cfctrl *ctrl,
 					      struct cfctrl_request_info *req)
 {
-	struct cfctrl_request_info *p;
-	struct cfctrl_request_info *ret;
+	struct cfctrl_request_info *p, *tmp, *first;
 
 	spin_lock(&ctrl->info_list_lock);
-	if (ctrl->first_req == NULL) {
-		spin_unlock(&ctrl->info_list_lock);
-		return NULL;
-	}
+	first = list_first_entry(&ctrl->list, struct cfctrl_request_info, list);
 
-	if (cfctrl_req_eq(req, ctrl->first_req)) {
-		ret = ctrl->first_req;
-		caif_assert(ctrl->first_req);
-		atomic_set(&ctrl->rsp_seq_no,
-				 ctrl->first_req->sequence_no);
-		ctrl->first_req = ctrl->first_req->next;
-		spin_unlock(&ctrl->info_list_lock);
-		return ret;
-	}
-
-	p = ctrl->first_req;
-
-	while (p->next != NULL) {
-		if (cfctrl_req_eq(req, p->next)) {
+	list_for_each_entry_safe(p, tmp, &ctrl->list, list) {
+		if (cfctrl_req_eq(req, p)) {
+			if (p != first)
 				pr_warning("CAIF: %s(): Requests are not "
 					"received in order\n",
 					__func__);
-			ret = p->next;
+
 			atomic_set(&ctrl->rsp_seq_no,
-					p->next->sequence_no);
-			p->next = p->next->next;
-			spin_unlock(&ctrl->info_list_lock);
-			return ret;
+					 p->sequence_no);
+			list_del(&p->list);
+			goto out;
 		}
-		p = p->next;
 	}
+	p = NULL;
+out:
 	spin_unlock(&ctrl->info_list_lock);
-
-	pr_warning("CAIF: %s(): Request does not match\n",
-		   __func__);
-	return NULL;
+	return p;
 }
 
 struct cfctrl_rsp *cfctrl_get_respfuncs(struct cflayer *layer)
@@ -388,31 +361,18 @@ void cfctrl_getstartreason_req(struct cflayer *layer)
 
 void cfctrl_cancel_req(struct cflayer *layr, struct cflayer *adap_layer)
 {
-	struct cfctrl_request_info *p, *req;
+	struct cfctrl_request_info *p, *tmp;
 	struct cfctrl *ctrl = container_obj(layr);
 	spin_lock(&ctrl->info_list_lock);
+	pr_warning("CAIF: %s(): enter\n", __func__);
 
-	if (ctrl->first_req == NULL) {
-		spin_unlock(&ctrl->info_list_lock);
-		return;
-	}
-
-	if (ctrl->first_req->client_layer == adap_layer) {
-
-		req = ctrl->first_req;
-		ctrl->first_req = ctrl->first_req->next;
-		kfree(req);
-	}
-
-	p = ctrl->first_req;
-	while (p != NULL && p->next != NULL) {
-		if (p->next->client_layer == adap_layer) {
-
-			req = p->next;
-			p->next = p->next->next;
-			kfree(p->next);
+	list_for_each_entry_safe(p, tmp, &ctrl->list, list) {
+		if (p->client_layer == adap_layer) {
+			pr_warning("CAIF: %s(): cancel req :%d\n", __func__,
+					p->sequence_no);
+			list_del(&p->list);
+			kfree(p);
 		}
-		p = p->next;
 	}
 
 	spin_unlock(&ctrl->info_list_lock);
@@ -634,7 +594,7 @@ static void cfctrl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
 	case _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND:
 	case CAIF_CTRLCMD_FLOW_OFF_IND:
 		spin_lock(&this->info_list_lock);
-		if (this->first_req != NULL) {
+		if (!list_empty(&this->list)) {
 			pr_debug("CAIF: %s(): Received flow off in "
 				   "control layer", __func__);
 		}