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From:   Muchun Song <songmuchun@bytedance.com>
To:     corbet@lwn.net, mike.kravetz@oracle.com, akpm@linux-foundation.org,
        mcgrof@kernel.org, keescook@chromium.org, yzaikin@google.com,
        osalvador@suse.de, david@redhat.com
Cc:     linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, duanxiongchun@bytedance.com, smuchun@gmail.com,
        Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH v4 3/4] sysctl: allow to set extra1 to SYSCTL_ONE
Date:   Fri, 18 Mar 2022 18:07:19 +0800
Message-Id: <20220318100720.14524-4-songmuchun@bytedance.com>
In-Reply-To: <20220318100720.14524-1-songmuchun@bytedance.com>
References: <20220318100720.14524-1-songmuchun@bytedance.com>
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proc_do_static_key() does not consider the situation where a sysctl is only
allowed to be enabled and cannot be disabled under certain circumstances
since it set "->extra1" to SYSCTL_ZERO unconditionally.  This patch add the
functionality to set "->extra1" accordingly.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 kernel/sysctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 770d5f7c7ae4..1e89c3e428ad 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1638,7 +1638,7 @@ int proc_do_static_key(struct ctl_table *table, int write,
 		.data   = &val,
 		.maxlen = sizeof(val),
 		.mode   = table->mode,
-		.extra1 = SYSCTL_ZERO,
+		.extra1 = table->extra1 == SYSCTL_ONE ? SYSCTL_ONE : SYSCTL_ZERO,
 		.extra2 = SYSCTL_ONE,
 	};
 
-- 
2.11.0