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From:   Wei Yang <richard.weiyang@gmail.com>
To:     tj@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org
Cc:     cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
        Wei Yang <richard.weiyang@gmail.com>
Subject: [PATCH 3/4] cgroup: simplify the cgroup descendant helper
Date:   Mon,  4 Oct 2021 08:49:27 +0000
Message-Id: <20211004084928.17622-3-richard.weiyang@gmail.com>
In-Reply-To: <20211004084928.17622-1-richard.weiyang@gmail.com>
References: <20211004084928.17622-1-richard.weiyang@gmail.com>
Precedence: bulk

cgroup_for_each_live_descendant_[pre|post] use cgroup_css() to get the
root. While since the 2nd parameter is NULL, cgroup_css() always return
cgrp->self.

Let's simplify this a little.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
 kernel/cgroup/cgroup.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 570b0c97392a..457353aeb0ca 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -732,7 +732,7 @@ EXPORT_SYMBOL_GPL(of_css);
 
 /* walk live descendants in pre order */
 #define cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp)		\
-	css_for_each_descendant_pre((d_css), cgroup_css((cgrp), NULL))	\
+	css_for_each_descendant_pre((d_css), &(cgrp)->self)		\
 		if (({ lockdep_assert_held(&cgroup_mutex);		\
 		       (dsct) = (d_css)->cgroup;			\
 		       cgroup_is_dead(dsct); }))			\
@@ -741,7 +741,7 @@ EXPORT_SYMBOL_GPL(of_css);
 
 /* walk live descendants in postorder */
 #define cgroup_for_each_live_descendant_post(dsct, d_css, cgrp)		\
-	css_for_each_descendant_post((d_css), cgroup_css((cgrp), NULL))	\
+	css_for_each_descendant_post((d_css), &(cgrp)->self)		\
 		if (({ lockdep_assert_held(&cgroup_mutex);		\
 		       (dsct) = (d_css)->cgroup;			\
 		       cgroup_is_dead(dsct); }))			\
-- 
2.23.0