cgroup: list_for_each cleanup

--------------------------
while() {
	list_entry();
	...
}
--------------------------

is equivalent to following code.

--------------------------
list_for_each_entry(){
	...
}
--------------------------

later can review easily more.

this patch is just clean up.
it doesn't have any behavor change.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 21 insertions, 23 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index f50edadfdd86..6836a9063634 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -241,17 +241,20 @@ static int use_task_css_set_links;
  */
 static void unlink_css_set(struct css_set *cg)
 {
+        struct cg_cgroup_link *link;
+        struct cg_cgroup_link *saved_link;
+
         write_lock(&css_set_lock);
         hlist_del(&cg->hlist);
         css_set_count--;
-        while (!list_empty(&cg->cg_links)) {
-                struct cg_cgroup_link *link;
-                link = list_entry(cg->cg_links.next,
-                                  struct cg_cgroup_link, cg_link_list);
+
+        list_for_each_entry_safe(link, saved_link, &cg->cg_links,
+                                 cg_link_list) {
                 list_del(&link->cg_link_list);
                 list_del(&link->cgrp_link_list);
                 kfree(link);
         }
+
         write_unlock(&css_set_lock);
 }
 
@@ -363,15 +366,14 @@ static struct css_set *find_existing_css_set(
 static int allocate_cg_links(int count, struct list_head *tmp)
 {
         struct cg_cgroup_link *link;
+        struct cg_cgroup_link *saved_link;
         int i;
         INIT_LIST_HEAD(tmp);
         for (i = 0; i < count; i++) {
                 link = kmalloc(sizeof(*link), GFP_KERNEL);
                 if (!link) {
-                        while (!list_empty(tmp)) {
-                                link = list_entry(tmp->next,
-                                                  struct cg_cgroup_link,
-                                                  cgrp_link_list);
+                        list_for_each_entry_safe(link, saved_link, tmp,
+                                                 cgrp_link_list) {
                                 list_del(&link->cgrp_link_list);
                                 kfree(link);
                         }
@@ -384,11 +386,10 @@ static int allocate_cg_links(int count, struct list_head *tmp)
 
 static void free_cg_links(struct list_head *tmp)
 {
-        while (!list_empty(tmp)) {
-                struct cg_cgroup_link *link;
-                link = list_entry(tmp->next,
-                                  struct cg_cgroup_link,
-                                  cgrp_link_list);
+        struct cg_cgroup_link *link;
+        struct cg_cgroup_link *saved_link;
+
+        list_for_each_entry_safe(link, saved_link, tmp, cgrp_link_list) {
                 list_del(&link->cgrp_link_list);
                 kfree(link);
         }
@@ -1093,6 +1094,8 @@ static void cgroup_kill_sb(struct super_block *sb) {
         struct cgroupfs_root *root = sb->s_fs_info;
         struct cgroup *cgrp = &root->top_cgroup;
         int ret;
+        struct cg_cgroup_link *link;
+        struct cg_cgroup_link *saved_link;
 
         BUG_ON(!root);
 
@@ -1112,10 +1115,9 @@ static void cgroup_kill_sb(struct super_block *sb) {
          * root cgroup
          */
         write_lock(&css_set_lock);
-        while (!list_empty(&cgrp->css_sets)) {
-                struct cg_cgroup_link *link;
-                link = list_entry(cgrp->css_sets.next,
-                                  struct cg_cgroup_link, cgrp_link_list);
+
+        list_for_each_entry_safe(link, saved_link, &cgrp->css_sets,
+                                 cgrp_link_list) {
                 list_del(&link->cg_link_list);
                 list_del(&link->cgrp_link_list);
                 kfree(link);
@@ -1756,15 +1758,11 @@ int cgroup_add_files(struct cgroup *cgrp,
 int cgroup_task_count(const struct cgroup *cgrp)
 {
         int count = 0;
-        struct list_head *l;
+        struct cg_cgroup_link *link;
 
         read_lock(&css_set_lock);
-        l = cgrp->css_sets.next;
-        while (l != &cgrp->css_sets) {
-                struct cg_cgroup_link *link =
-                        list_entry(l, struct cg_cgroup_link, cgrp_link_list);
+        list_for_each_entry(link, &cgrp->css_sets, cgrp_link_list) {
                 count += atomic_read(&link->cg->ref.refcount);
-                l = l->next;
         }
         read_unlock(&css_set_lock);
         return count;