lib: Revise implementation of list

Adds LGPL license to the ouroboros lists.

12 files changed, 110 insertions, 276 deletions

diff --git a/include/ouroboros/list.h b/include/ouroboros/list.h
index 91fe6660..debc6742 100644
--- a/include/ouroboros/list.h
+++ b/include/ouroboros/list.h
@@ -3,171 +3,57 @@
  *
  * Simple doubly linked list implementation.
  *
- * Some of the internal functions ("__xxx") are useful when
- * manipulating whole lists rather than single entries, as
- * sometimes we already know the next/prev entries and we can
- * generate better code by using them directly rather than
- * using the generic single-entry routines.
+ *    Sander Vrijders    <sander.vrijders@intec.ugent.be>
+ *    Dimitri Staessense <dimitri.staessens@intec.ugent.be>
  *
- *    Sander Vrijders <sander.vrijders@intec.ugent.be>
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
+ * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
  */
 
 #ifndef OUROBOROS_LIST_H
 #define OUROBOROS_LIST_H
 
-/*
- * This file is from the Linux Kernel (include/linux/list.h)
- * and modified by simply removing hardware prefetching of list items.
- * Here by copyright, credits attributed to wherever they belong.
- * Kulesh Shanmugasundaram (kulesh [squiggly] isis.poly.edu)
- */
+#include <stdbool.h>
+#include <sys/types.h>
 
 struct list_head {
-        struct list_head * next, * prev;
+        struct list_head * nxt, * prv;
 };
 
-#define LIST_HEAD_INIT(name) { &(name), &(name) }
-
-#define LIST_HEAD(name)                                 \
-        struct list_head name = LIST_HEAD_INIT(name)
+#define list_entry(ptr, type, mbr)                              \
+        ((type *)((char *)(ptr)-(size_t)(&((type *)0)->mbr)))
 
-#define INIT_LIST_HEAD(ptr) do {                                \
-                (ptr)->next = (ptr); (ptr)->prev = (ptr);       \
-        } while (0)
-
-/**
- * list_add - add a new entry
- * @new: new entry to be added
- * @head: list head to add it after
- *
- * Insert a new entry after the specified head.
- * This is good for implementing stacks.
- */
-void list_add(struct list_head * new,
-              struct list_head * head);
+#define list_first_entry(ptr, type, mbr)        \
+        list_entry((ptr)->nxt, type, mbr)
 
-/**
- * list_add_tail - add a new entry
- * @new: new entry to be added
- * @head: list head to add it before
- *
- * Insert a new entry before the specified head.
- * This is useful for implementing queues.
- */
-void list_add_tail(struct list_head * new,
-                   struct list_head * head);
+#define list_for_each(p, h)                             \
+        for (p = (h)->nxt; p != (h); p = p->nxt)
 
-/**
- * list_del - deletes entry from list.
- * @entry: the element to delete from the list.
- * Note: list_empty on entry does not return true after this,
- * the entry is in an undefined state.
- */
-void list_del(struct list_head * entry);
+#define list_for_each_safe(p, t, h)               \
+        for (p = (h)->nxt, t = p->nxt; p != (h);  \
+             p = t, t = p->nxt)
 
-/**
- * list_del_init - deletes entry from list and reinitialize it.
- * @entry: the element to delete from the list.
- */
-void list_del_init(struct list_head * entry);
+void list_head_init(struct list_head * h);
 
-/**
- * list_move - delete from one list and add as another's head
- * @list: the entry to move
- * @head: the head that will precede our entry
- */
-void list_move(struct list_head * list,
-               struct list_head * head);
+void list_add(struct list_head * e,
+              struct list_head * h);
 
-/**
- * list_move_tail - delete from one list and add as another's tail
- * @list: the entry to move
- * @head: the head that will follow our entry
- */
-void list_move_tail(struct list_head * list,
-                    struct list_head * head);
+void list_add_tail(struct list_head * e,
+                   struct list_head * h);
 
-/**
- * list_empty - tests whether a list is empty
- * @head: the list to test.
- */
-int list_empty(struct list_head * head);
+void list_del(struct list_head * e);
 
-/**
- * list_splice - join two lists
- * @list: the new list to add.
- * @head: the place to add it in the first list.
- */
-void list_splice(struct list_head * list,
-                 struct list_head * head);
-
-/**
- * list_splice_init - join two lists and reinitialise the emptied list.
- * @list: the new list to add.
- * @head: the place to add it in the first list.
- *
- * The list at @list is reinitialised
- */
-void list_splice_init(struct list_head * list,
-                      struct list_head * head);
-
-/**
- * list_entry - get the struct for this entry
- * @ptr:        the &struct list_head pointer.
- * @type:       the type of the struct this is embedded in.
- * @member:     the name of the list_struct within the struct.
- */
-#define list_entry(ptr, type, member)                                   \
-        ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
-
-/**
- * list_first_entry - get the struct for the first entry
- * expects the list to be non-empty
- * @ptr:        the &struct list_head pointer.
- * @type:       the type of the struct this is embedded in.
- * @member:     the name of the list_struct within the struct.
- */
-#define list_first_entry(ptr, type, member) \
-        list_entry((ptr)->next, type, member)
-
-/**
- * list_for_each - iterate over a list
- * @pos:        the &struct list_head to use as a loop counter.
- * @head:       the head for your list.
- */
-#define list_for_each(pos, head)                \
-        for (pos = (head)->next; pos != (head); \
-             pos = pos->next)
-/**
- * list_for_each_prev   -       iterate over a list backwards
- * @pos:        the &struct list_head to use as a loop counter.
- * @head:       the head for your list.
- */
-#define list_for_each_prev(pos, head)           \
-        for (pos = (head)->prev; pos != (head); \
-             pos = pos->prev)
-
-/**
- * list_for_each_safe - iterate over a list safe against removal of list entry
- * @pos:        the &struct list_head to use as a loop counter.
- * @n:          another &struct list_head to use as temporary storage
- * @head:       the head for your list.
- */
-#define list_for_each_safe(pos, n, head)                        \
-        for (pos = (head)->next, n = pos->next; pos != (head);  \
-             pos = n, n = pos->next)
+bool list_is_empty(struct list_head * h);
 
 #endif
diff --git a/src/ipcpd/ipcp-data.c b/src/ipcpd/ipcp-data.c
index 132684c2..2d1d2752 100644
--- a/src/ipcpd/ipcp-data.c
+++ b/src/ipcpd/ipcp-data.c
@@ -119,9 +119,9 @@ struct ipcp_data * ipcp_data_init(struct ipcp_data * dst,
         dst->dif_name = NULL;
 
         /* init the lists */
-        INIT_LIST_HEAD(&dst->registry);
-        INIT_LIST_HEAD(&dst->directory);
-        INIT_LIST_HEAD(&dst->dir_queries);
+        list_head_init(&dst->registry);
+        list_head_init(&dst->directory);
+        list_head_init(&dst->dir_queries);
 
         /* init the locks */
         pthread_rwlock_init(&dst->reg_lock, NULL);
@@ -437,7 +437,7 @@ struct dir_query * ipcp_data_dir_query_create(char * name)
         pthread_cond_init(&query->cond, &cattr);
         pthread_mutex_init(&query->lock, NULL);
 
-        INIT_LIST_HEAD(&query->next);
+        list_head_init(&query->next);
 
         return query;
 }
diff --git a/src/ipcpd/normal/ribmgr.c b/src/ipcpd/normal/ribmgr.c
index e52db08a..6356d48c 100644
--- a/src/ipcpd/normal/ribmgr.c
+++ b/src/ipcpd/normal/ribmgr.c
@@ -471,9 +471,9 @@ static int write_ro_msg(struct cdap *    neighbor,
 
 int ribmgr_init()
 {
-        INIT_LIST_HEAD(&rib.flows);
-        INIT_LIST_HEAD(&rib.subs);
-        INIT_LIST_HEAD(&rib.ro_ids);
+        list_head_init(&rib.flows);
+        list_head_init(&rib.subs);
+        list_head_init(&rib.ro_ids);
 
         rib.root = malloc(sizeof(*(rib.root)));
         if (rib.root == NULL)
@@ -993,7 +993,7 @@ static int ro_id_create(char * name, ro_msg_t * msg)
 
         tmp->seqno = msg->seqno;
         tmp->full_name = strdup(name);
-        INIT_LIST_HEAD(&tmp->next);
+        list_head_init(&tmp->next);
 
         if (tmp->full_name == NULL) {
                 free(tmp);
@@ -1154,7 +1154,7 @@ static int ribmgr_add_flow(int fd)
                 return -1;
         }
 
-        INIT_LIST_HEAD(&flow->next);
+        list_head_init(&flow->next);
         flow->instance = instance;
         flow->fd = fd;
 
@@ -1310,7 +1310,7 @@ int ribmgr_enrol()
 
         pthread_rwlock_wrlock(&rib.flows_lock);
 
-        assert(!list_empty(&rib.flows));
+        assert(!list_is_empty(&rib.flows));
 
         flow = list_first_entry((&rib.flows), struct mgmt_flow, next);
         instance = flow->instance;
@@ -1631,7 +1631,7 @@ int ro_subscribe(const char * name, struct ro_sub_ops * ops)
         if (sub == NULL)
                 return -ENOMEM;
 
-        INIT_LIST_HEAD(&sub->next);
+        list_head_init(&sub->next);
 
         sub->name = strdup(name);
         if (sub->name == NULL) {
diff --git a/src/ipcpd/timerwheel.c b/src/ipcpd/timerwheel.c
index 4ef7ce2f..1d842c8f 100644
--- a/src/ipcpd/timerwheel.c
+++ b/src/ipcpd/timerwheel.c
@@ -232,7 +232,7 @@ struct timerwheel * timerwheel_create(unsigned int resolution,
         tw->intv.tv_sec = (tw->resolution / FRAC) / 1000;
         tw->intv.tv_nsec = ((tw->resolution / FRAC) % 1000) * MILLION;
 
-        INIT_LIST_HEAD(&tw->wq);
+        list_head_init(&tw->wq);
 
         if (pthread_mutex_init(&tw->lock, NULL)) {
                 LOG_DBG("Could not init mutex.");
@@ -265,7 +265,7 @@ struct timerwheel * timerwheel_create(unsigned int resolution,
         now.tv_nsec -= (now.tv_nsec % MILLION);
 
         for (i = 0; i < tw->elements; ++i) {
-                INIT_LIST_HEAD(&tw->wheel[i].funcs);
+                list_head_init(&tw->wheel[i].funcs);
                 tw->wheel[i].expiry = now;
                 ts_add(&now, &res_ts, &now);
         }
diff --git a/src/irmd/api_table.c b/src/irmd/api_table.c
index 97b8eb0f..4b9d9ecb 100644
--- a/src/irmd/api_table.c
+++ b/src/irmd/api_table.c
@@ -42,8 +42,8 @@ struct api_entry * api_entry_create(pid_t api, char * apn)
         if (e == NULL)
                 return NULL;
 
-        INIT_LIST_HEAD(&e->next);
-        INIT_LIST_HEAD(&e->names);
+        list_head_init(&e->next);
+        list_head_init(&e->names);
 
         e->api      = api;
         e->apn      = apn;
diff --git a/src/irmd/apn_table.c b/src/irmd/apn_table.c
index 34983f78..7edba361 100644
--- a/src/irmd/apn_table.c
+++ b/src/irmd/apn_table.c
@@ -41,8 +41,8 @@ struct apn_entry * apn_entry_create(char * apn,
         if (e == NULL)
                 return NULL;
 
-        INIT_LIST_HEAD(&e->next);
-        INIT_LIST_HEAD(&e->names);
+        list_head_init(&e->next);
+        list_head_init(&e->names);
 
         e->apn   = apn;
         e->ap    = ap;
diff --git a/src/irmd/main.c b/src/irmd/main.c
index b7292e74..295e3320 100644
--- a/src/irmd/main.c
+++ b/src/irmd/main.c
@@ -150,7 +150,7 @@ static struct ipcp_entry * ipcp_entry_create(void)
         e->name = NULL;
         e->dif_name = NULL;
 
-        INIT_LIST_HEAD(&e->next);
+        list_head_init(&e->next);
 
         return e;
 }
@@ -260,7 +260,7 @@ static pid_t create_ipcp(char * name, enum ipcp_type ipcp_type)
                 return -1;
         }
 
-        INIT_LIST_HEAD(&tmp->next);
+        list_head_init(&tmp->next);
 
         tmp->api = api->pid;
         tmp->name = strdup(name);
@@ -743,7 +743,7 @@ static int name_reg(char * name, char ** difs, size_t len)
 
         pthread_rwlock_wrlock(&irmd->reg_lock);
 
-        if (list_empty(&irmd->ipcps)) {
+        if (list_is_empty(&irmd->ipcps)) {
                 pthread_rwlock_unlock(&irmd->reg_lock);
                 pthread_rwlock_unlock(&irmd->state_lock);
                 return -1;
@@ -1988,12 +1988,12 @@ static int irm_create(void)
                 return -1;
         }
 
-        INIT_LIST_HEAD(&irmd->ipcps);
-        INIT_LIST_HEAD(&irmd->api_table);
-        INIT_LIST_HEAD(&irmd->apn_table);
-        INIT_LIST_HEAD(&irmd->spawned_apis);
-        INIT_LIST_HEAD(&irmd->registry);
-        INIT_LIST_HEAD(&irmd->irm_flows);
+        list_head_init(&irmd->ipcps);
+        list_head_init(&irmd->api_table);
+        list_head_init(&irmd->apn_table);
+        list_head_init(&irmd->spawned_apis);
+        list_head_init(&irmd->registry);
+        list_head_init(&irmd->irm_flows);
 
         irmd->port_ids = bmp_create(IRMD_MAX_FLOWS, 0);
         if (irmd->port_ids == NULL) {
diff --git a/src/irmd/registry.c b/src/irmd/registry.c
index 34d0a921..e1f8419e 100644
--- a/src/irmd/registry.c
+++ b/src/irmd/registry.c
@@ -63,10 +63,10 @@ static struct reg_entry * reg_entry_init(struct reg_entry * e,
         if (e == NULL || name == NULL)
                 return NULL;
 
-        INIT_LIST_HEAD(&e->next);
-        INIT_LIST_HEAD(&e->difs);
-        INIT_LIST_HEAD(&e->reg_apns);
-        INIT_LIST_HEAD(&e->reg_apis);
+        list_head_init(&e->next);
+        list_head_init(&e->difs);
+        list_head_init(&e->reg_apns);
+        list_head_init(&e->reg_apis);
 
         e->name = name;
 
@@ -228,7 +228,7 @@ void reg_entry_del_apn(struct reg_entry * e, char * apn)
                 }
         }
 
-        if (e->state == REG_NAME_AUTO_ACCEPT && list_empty(&e->reg_apns)) {
+        if (e->state == REG_NAME_AUTO_ACCEPT && list_is_empty(&e->reg_apns)) {
                 e->state = REG_NAME_IDLE;
                 pthread_cond_broadcast(&e->state_cond);
         }
@@ -237,7 +237,7 @@ void reg_entry_del_apn(struct reg_entry * e, char * apn)
 
 char * reg_entry_get_apn(struct reg_entry * e)
 {
-        if (!list_empty(&e->reg_apis) || list_empty(&e->reg_apns))
+        if (!list_is_empty(&e->reg_apis) || list_is_empty(&e->reg_apns))
                 return NULL;
 
         return list_first_entry(&e->reg_apns, struct str_el, next)->str;
@@ -311,8 +311,8 @@ void reg_entry_del_api(struct reg_entry * e, pid_t api)
                 }
         }
 
-        if (list_empty(&e->reg_apis)) {
-                if (!list_empty(&e->reg_apns))
+        if (list_is_empty(&e->reg_apis)) {
+                if (!list_is_empty(&e->reg_apns))
                         e->state = REG_NAME_AUTO_ACCEPT;
                 else
                         e->state = REG_NAME_IDLE;
@@ -328,7 +328,7 @@ pid_t reg_entry_get_api(struct reg_entry * e)
         if (e == NULL)
                 return -1;
 
-        if (list_empty(&e->reg_apis))
+        if (list_is_empty(&e->reg_apis))
                 return -1;
 
         return list_first_entry(&e->reg_apis, struct pid_el, next)->pid;
diff --git a/src/lib/cdap.c b/src/lib/cdap.c
index 17104770..869e929d 100644
--- a/src/lib/cdap.c
+++ b/src/lib/cdap.c
@@ -365,8 +365,8 @@ struct cdap * cdap_create(int fd)
                 return NULL;
         }
 
-        INIT_LIST_HEAD(&instance->sent);
-        INIT_LIST_HEAD(&instance->rcvd);
+        list_head_init(&instance->sent);
+        list_head_init(&instance->rcvd);
 
         instance->fd = fd;
 
@@ -573,7 +573,7 @@ cdap_key_t cdap_request_wait(struct cdap *      instance,
         pthread_cleanup_push((void(*)(void *))pthread_mutex_unlock,
                              (void *) &instance->rcvd_lock);
 
-        while (list_empty(&instance->rcvd))
+        while (list_is_empty(&instance->rcvd))
                 pthread_cond_wait(&instance->rcvd_cond, &instance->rcvd_lock);
 
         rcvd = list_first_entry(&instance->rcvd, struct cdap_rcvd, next);
diff --git a/src/lib/cdap_req.c b/src/lib/cdap_req.c
index 57ad22c5..0c0d98c0 100644
--- a/src/lib/cdap_req.c
+++ b/src/lib/cdap_req.c
@@ -51,7 +51,7 @@ struct cdap_req * cdap_req_create(cdap_key_t key)
         pthread_cond_init(&creq->cond, &cattr);
         pthread_mutex_init(&creq->lock, NULL);
 
-        INIT_LIST_HEAD(&creq->next);
+        list_head_init(&creq->next);
 
         clock_gettime(PTHREAD_COND_CLOCK, &creq->birth);
 
diff --git a/src/lib/hashtable.c b/src/lib/hashtable.c
index 8dcd4ec1..e2b00de0 100644
--- a/src/lib/hashtable.c
+++ b/src/lib/hashtable.c
@@ -69,7 +69,7 @@ struct htable * htable_create(uint64_t buckets, bool hash_key)
         }
 
         for (i = 0; i < buckets; i++)
-                INIT_LIST_HEAD(&(tmp->buckets[i]));
+                list_head_init(&(tmp->buckets[i]));
 
         return tmp;
 }
@@ -136,7 +136,7 @@ int htable_insert(struct htable * table, uint64_t key, void * val)
 
         entry->key = key;
         entry->val = val;
-        INIT_LIST_HEAD(&entry->next);
+        list_head_init(&entry->next);
 
         list_add(&entry->next, &(table->buckets[lookup_key]));
 
diff --git a/src/lib/list.c b/src/lib/list.c
index 0f3493e3..6bdb3461 100644
--- a/src/lib/list.c
+++ b/src/lib/list.c
@@ -3,122 +3,70 @@
  *
  * Simple doubly linked list implementation.
  *
- * Some of the internal functions ("__xxx") are useful when
- * manipulating whole lists rather than single entries, as
- * sometimes we already know the next/prev entries and we can
- * generate better code by using them directly rather than
- * using the generic single-entry routines.
+ *    Sander Vrijders    <sander.vrijders@intec.ugent.be>
+ *    Dimitri Staessense <dimitri.staessens@intec.ugent.be>
  *
- * This file is from the Linux Kernel (include/linux/list.h)
- * and modified by simply removing hardware prefetching of list items.
- * Here by copyright, credits attributed to wherever they belong.
- * Kulesh Shanmugasundaram (kulesh [squiggly] isis.poly.edu)
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
  *
- *    Sander Vrijders <sander.vrijders@intec.ugent.be>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
+ * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
  */
 
 #include <ouroboros/list.h>
 
-static void __list_add(struct list_head * new,
-                       struct list_head * prev,
-                       struct list_head * next)
-{
-        next->prev = new;
-        new->next = next;
-        new->prev = prev;
-        prev->next = new;
-}
-
-void list_add(struct list_head * new,
-              struct list_head * head)
-{
-        __list_add(new, head, head->next);
-}
-
-void list_add_tail(struct list_head * new,
-                   struct list_head * head)
-{
-        __list_add(new, head->prev, head);
-}
-
-static void __list_del(struct list_head * prev,
-                       struct list_head * next)
-{
-        next->prev = prev;
-        prev->next = next;
-}
+#include <stddef.h>
 
-void list_del(struct list_head * entry)
+void list_head_init(struct list_head * h)
 {
-        __list_del(entry->prev, entry->next);
-        entry->next = (void *) 0;
-        entry->prev = (void *) 0;
+        h->nxt = h;
+        h->prv = h;
 }
 
-void list_del_init(struct list_head * entry)
+static void add_list(struct list_head * n,
+                     struct list_head * prv,
+                     struct list_head * nxt)
 {
-        __list_del(entry->prev, entry->next);
-        INIT_LIST_HEAD(entry);
+        nxt->prv = n;
+        n->nxt = nxt;
+        n->prv = prv;
+        prv->nxt = n;
 }
 
-void list_move(struct list_head * list,
-               struct list_head * head)
+static void del_list(struct list_head * prv,
+                     struct list_head * nxt)
 {
-        __list_del(list->prev, list->next);
-        list_add(list, head);
+        nxt->prv = prv;
+        prv->nxt = nxt;
 }
 
-void list_move_tail(struct list_head * list,
-                    struct list_head * head)
+void list_add(struct list_head * n,
+              struct list_head * h)
 {
-        __list_del(list->prev, list->next);
-        list_add_tail(list, head);
+        add_list(n, h, h->nxt);
 }
 
-int list_empty(struct list_head * head)
+void list_add_tail(struct list_head * n,
+                   struct list_head * h)
 {
-        return head->next == head;
-}
-
-static void __list_splice(struct list_head *list,
-                          struct list_head *head)
-{
-        struct list_head *first = list->next;
-        struct list_head *last = list->prev;
-        struct list_head *at = head->next;
-
-        first->prev = head;
-        head->next = first;
-
-        last->next = at;
-        at->prev = last;
+        add_list(n, h->prv, h);
 }
 
-void list_splice(struct list_head * list,
-                 struct list_head * head)
+void list_del(struct list_head * e)
 {
-        if (!list_empty(list))
-                __list_splice(list, head);
+        del_list(e->prv, e->nxt);
+        e->nxt = e->prv = NULL;
 }
 
-void list_splice_init(struct list_head * list,
-                      struct list_head * head)
+bool list_is_empty(struct list_head * h)
 {
-        if (!list_empty(list)) {
-                __list_splice(list, head);
-                INIT_LIST_HEAD(list);
-        }
+        return h->nxt == h;
 }