[SRU][J][PATCH 4/5] cgroup.c: add helper __cset_cgroup_from_root to cleanup duplicated codes

[Philip Cox]

From: Lin Feng <linf at wangsu.com>

No funtionality change, but save us some lines.

Signed-off-by: Lin Feng <linf at wangsu.com>
Acked-by: Mukesh Ojha <quic_mojha at quicinc.com>
Signed-off-by: Tejun Heo <tj at kernel.org>
(cherry picked from commit e210a89f5b07680fe21d21e846e6817346c5ba3b)
Signed-off-by: Philip Cox <philip.cox at canonical.com>
---
 kernel/cgroup/cgroup.c | 58 ++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 31 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 3431bc2c6d0eb..da2b61f60bfb8 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1378,6 +1378,31 @@ static void cgroup_destroy_root(struct cgroup_root *root)
 	cgroup_free_root(root);
 }
 
+static inline struct cgroup *__cset_cgroup_from_root(struct css_set *cset,
+					    struct cgroup_root *root)
+{
+	struct cgroup *res_cgroup = NULL;
+
+	if (cset == &init_css_set) {
+		res_cgroup = &root->cgrp;
+	} else if (root == &cgrp_dfl_root) {
+		res_cgroup = cset->dfl_cgrp;
+	} else {
+		struct cgrp_cset_link *link;
+
+		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
+			struct cgroup *c = link->cgrp;
+
+			if (c->root == root) {
+				res_cgroup = c;
+				break;
+			}
+		}
+	}
+
+	return res_cgroup;
+}
+
 /*
  * look up cgroup associated with current task's cgroup namespace on the
  * specified hierarchy
@@ -1393,22 +1418,8 @@ current_cgns_cgroup_from_root(struct cgroup_root *root)
 	rcu_read_lock();
 
 	cset = current->nsproxy->cgroup_ns->root_cset;
-	if (cset == &init_css_set) {
-		res = &root->cgrp;
-	} else if (root == &cgrp_dfl_root) {
-		res = cset->dfl_cgrp;
-	} else {
-		struct cgrp_cset_link *link;
-
-		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
-			struct cgroup *c = link->cgrp;
+	res = __cset_cgroup_from_root(cset, root);
 
-			if (c->root == root) {
-				res = c;
-				break;
-			}
-		}
-	}
 	rcu_read_unlock();
 
 	return res;
@@ -1422,22 +1433,7 @@ static struct cgroup *cset_cgroup_from_root(struct css_set *cset,
 
 	lockdep_assert_held(&css_set_lock);
 
-	if (cset == &init_css_set) {
-		res = &root->cgrp;
-	} else if (root == &cgrp_dfl_root) {
-		res = cset->dfl_cgrp;
-	} else {
-		struct cgrp_cset_link *link;
-
-		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
-			struct cgroup *c = link->cgrp;
-
-			if (c->root == root) {
-				res = c;
-				break;
-			}
-		}
-	}
+	res = __cset_cgroup_from_root(cset, root);
 
 	BUG_ON(!res);
 	return res;
-- 
2.43.0