linux-kernel - [PATCH 03/11] kernel/kmod: move modprobe sysctl to its own file

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Date:   Sun, 20 Feb 2022 14:00:29 +0800
From:   tangmeng <tangmeng@...ontech.com>
To:     mcgrof@...nel.org, keescook@...omium.org, yzaikin@...gle.com
Cc:     linux-modules@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, nizhen@...ontech.com,
        zhanglianjie@...ontech.com, nixiaoming@...wei.com,
        tangmeng <tangmeng@...ontech.com>
Subject: [PATCH 03/11] kernel/kmod: move modprobe sysctl to its own file

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong.  The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

All filesystem syctls now get reviewed by fs folks. This commit
follows the commit of fs, move the modprobe sysctl to its own file,
kernel/kmod.c.

Signed-off-by: tangmeng <tangmeng@...ontech.com>
---
 include/linux/kmod.h |  3 ---
 kernel/kmod.c        | 23 ++++++++++++++++++++++-
 kernel/sysctl.c      |  7 -------
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index 68f69362d427..9a07c3215389 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -14,10 +14,7 @@
 #include <linux/workqueue.h>
 #include <linux/sysctl.h>
 
-#define KMOD_PATH_LEN 256
-
 #ifdef CONFIG_MODULES
-extern char modprobe_path[]; /* for sysctl */
 /* modprobe exit status on success, -ve on error.  Return value
  * usually useless though. */
 extern __printf(2, 3)
diff --git a/kernel/kmod.c b/kernel/kmod.c
index b717134ebe17..54df92abb8dd 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -55,10 +55,31 @@ static DECLARE_WAIT_QUEUE_HEAD(kmod_wq);
  */
 #define MAX_KMOD_ALL_BUSY_TIMEOUT 5
 
+#define KMOD_PATH_LEN 256
 /*
 	modprobe_path is set via /proc/sys.
 */
-char modprobe_path[KMOD_PATH_LEN] = CONFIG_MODPROBE_PATH;
+static char modprobe_path[KMOD_PATH_LEN] = CONFIG_MODPROBE_PATH;
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table kern_modprobe_table[] = {
+	{
+		.procname       = "modprobe",
+		.data           = &modprobe_path,
+		.maxlen         = KMOD_PATH_LEN,
+		.mode           = 0644,
+		.proc_handler   = proc_dostring,
+	},
+	{ }
+};
+
+static __init int kernel_modprobe_sysctls_init(void)
+{
+	register_sysctl_init("kernel", kern_modprobe_table);
+	return 0;
+}
+late_initcall(kernel_modprobe_sysctls_init);
+#endif /* CONFIG_SYSCTL */
 
 static void free_modprobe_argv(struct subprocess_info *info)
 {
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b41138d64e5e..126d47e8224d 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1791,13 +1791,6 @@ static struct ctl_table kern_table[] = {
 	},
 #endif
 #ifdef CONFIG_MODULES
-	{
-		.procname	= "modprobe",
-		.data		= &modprobe_path,
-		.maxlen		= KMOD_PATH_LEN,
-		.mode		= 0644,
-		.proc_handler	= proc_dostring,
-	},
 	{
 		.procname	= "modules_disabled",
 		.data		= &modules_disabled,
-- 
2.20.1