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From:   =?utf-8?q?Thomas_Wei=C3=9Fschuh?= <linux@weissschuh.net>
Date:   Sat, 25 Nov 2023 13:52:50 +0100
Subject: [PATCH RFC 1/7] sysctl: add helper sysctl_run_handler
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Message-Id: <20231125-const-sysctl-v1-1-5e881b0e0290@weissschuh.net>
References: <20231125-const-sysctl-v1-0-5e881b0e0290@weissschuh.net>
In-Reply-To: <20231125-const-sysctl-v1-0-5e881b0e0290@weissschuh.net>
To:     Kees Cook <keescook@chromium.org>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Iurii Zaikin <yzaikin@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Joel Granados <j.granados@samsung.com>
Cc:     linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org,
        =?utf-8?q?Thomas_Wei=C3=9Fschuh?= <linux@weissschuh.net>
Precedence: bulk

A future patch will introduce a second handler function.
To make the code future-proof add the sysctl_run_handler function that
automatically can call the correct handler function.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 fs/proc/proc_sysctl.c  | 2 +-
 include/linux/sysctl.h | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 8064ea76f80b..1bb0aa2ff501 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -597,7 +597,7 @@ static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter,
 		goto out_free_buf;
 
 	/* careful: calling conventions are nasty here */
-	error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos);
+	error = sysctl_run_handler(table, write, kbuf, &count, &iocb->ki_pos);
 	if (error)
 		goto out_free_buf;
 
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 61b40ea81f4d..604aaaa1fce2 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -298,4 +298,10 @@ static inline bool sysctl_is_alias(char *param)
 int sysctl_max_threads(struct ctl_table *table, int write, void *buffer,
 		size_t *lenp, loff_t *ppos);
 
+static inline int sysctl_run_handler(struct ctl_table *ctl, int write,
+				     void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return ctl->proc_handler(ctl, write, buffer, lenp, ppos);
+}
+
 #endif /* _LINUX_SYSCTL_H */

-- 
2.43.0