Re: [PATCH v2 6/8] inotify: simplify subdirectory registration with register_sysctl()

Luis Chamberlain
2021-11-24T14:36:25Z

On Wed, Nov 24, 2021 at 10:44:09AM +0100, Jan Kara wrote:
> On Tue 23-11-21 12:24:20, Luis Chamberlain wrote:
> > From: Xiaoming Ni <nixiaoming@huawei.com>
> >
> > There is no need to user boiler plate code to specify a set of base
> > directories we're going to stuff sysctls under. Simplify this by using
> > register_sysctl() and specifying the directory path directly.
> >
> > Move inotify_user sysctl to inotify_user.c while at it to remove clutter
> > from kernel/sysctl.c.
> >
> > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> > [mcgrof: update commit log to reflect new path we decided to take]
> > Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
>
> This looks fishy. You register inotify_table but not fanotify_table and
> remove both...

Indeed, the following was missing, I'll roll it in:

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 559bc1e9926d..a35693eb1f36 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -59,7 +59,7 @@ static int fanotify_max_queued_events __read_mostly;
static long ft_zero = 0;
static long ft_int_max = INT_MAX;

-struct ctl_table fanotify_table[] = {
+static struct ctl_table fanotify_table[] = {
{
.procname = "max_user_groups",
.data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS],
@@ -88,6 +88,13 @@ struct ctl_table fanotify_table[] = {
},
{ }
};
+
+static void __init fanotify_sysctls_init(void)
+{
+ register_sysctl("fs/fanotify", fanotify_table);
+}
+#else
+#define fanotify_sysctls_init() do { } while (0)
#endif /* CONFIG_SYSCTL */

/*
@@ -1685,6 +1692,7 @@ static int __init fanotify_user_setup(void)
init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS] =
FANOTIFY_DEFAULT_MAX_GROUPS;
init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS] = max_marks;
+ fanotify_sysctls_init();

return 0;
}
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index 616af2ea20f3..556cc63c88ee 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -5,8 +5,6 @@
#include <linux/sysctl.h>
#include <uapi/linux/fanotify.h>

-extern struct ctl_table fanotify_table[]; /* for sysctl */
-
#define FAN_GROUP_FLAG(group, flag) \
((group)->fanotify_data.flags & (flag))