From ef15a6fe4d6ea114fe8d6cdcd4bf503aa1f183a8 Mon Sep 17 00:00:00 2001
From: Muchun Song <songmuchun@bytedance.com>
Date: Thu, 27 Jul 2023 11:42:30 +0800
Subject: [PATCH] mm: memcontrol: fix cannot alloc the maximum memcg ID

mainline inclusion
from mainline-v5.18-rc1
commit be740503ed03ea04ca362330baf082e6a38fe462
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7NXZ6?from=project-issue

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=be740503ed03ea04ca362330baf082e6a38fe462

--------------------------------

The idr_alloc() does not include @max ID.  So in the current
implementation, the maximum memcg ID is 65534 instead of 65535.  It
seems a bug.  So fix this.

Link: https://lkml.kernel.org/r/20220228122126.37293-15-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Conflict:
	mm/memcontrol.c
Signed-off-by: Lu Jialin <lujialin4@huawei.com>
(cherry picked from commit 763ab5c7b2f379c2c48f46f0d76be4d43bd0607b)
---
 mm/memcontrol.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 81429e8266ab..7f3832cedfdf 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5491,8 +5491,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
 		return ERR_PTR(error);
 
 	memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
-				 1, MEM_CGROUP_ID_MAX,
-				 GFP_KERNEL);
+				 1, MEM_CGROUP_ID_MAX + 1, GFP_KERNEL);
 	if (memcg->id.id < 0) {
 		error = memcg->id.id;
 		goto fail;
-- 
GitLab