The patch titled
Subject: sysctl: add helper to register a sysctl mount point
has been added to the -mm tree. Its filename is
sysctl-add-helper-to-register-a-sysctl-mount-point.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/sysctl-add-helper-to-register-a-sysctl-mount-point.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/sysctl-add-helper-to-register-a-sysctl-mount-point.patch
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------------------------------------------------------
From: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Subject: sysctl: add helper to register a sysctl mount point
The way to create a subdirectory on top of sysctl_mount_point is a bit
obscure, and *why* we do that even so more. Provide a helper which makes
it clear why we do this.
Link: https://lkml.kernel.org/r/20211124231435.1445213-4-mcgrof@xxxxxxxxxx
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Suggested-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Amir Goldstein <amir73il@xxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Antti Palosaari <crope@xxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Benjamin LaHaise <bcrl@xxxxxxxxx>
Cc: Clemens Ladisch <clemens@xxxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Iurii Zaikin <yzaikin@xxxxxxxxxx>
Cc: James E.J. Bottomley <jejb@xxxxxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: John Ogness <john.ogness@xxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Cc: Julia Lawall <julia.lawall@xxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Lukas Middendorf <kernel@xxxxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Phillip Potter <phil@xxxxxxxxxxxxxxxx>
Cc: Qing Wang <wangqing@xxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Sebastian Reichel <sre@xxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Stephen Kitt <steve@xxxxxxx>
Cc: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: Xiaoming Ni <nixiaoming@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/proc_sysctl.c | 13 +++++++++++++
include/linux/sysctl.h | 7 +++++++
2 files changed, 20 insertions(+)
--- a/fs/proc/proc_sysctl.c~sysctl-add-helper-to-register-a-sysctl-mount-point
+++ a/fs/proc/proc_sysctl.c
@@ -35,6 +35,19 @@ struct ctl_table sysctl_mount_point[] =
{ }
};
+/**
+ * register_sysctl_mount_point() - registers a sysctl mount point
+ * @path: path for the mount point
+ *
+ * Used to create a permanently empty directory to serve as mount point.
+ * There are some subtle but important permission checks this allows in the
+ * case of unprivileged mounts.
+ */
+struct ctl_table_header *register_sysctl_mount_point(const char *path)
+{
+ return register_sysctl(path, sysctl_mount_point);
+}
+
static bool is_empty_dir(struct ctl_table_header *head)
{
return head->ctl_table[0].child == sysctl_mount_point;
--- a/include/linux/sysctl.h~sysctl-add-helper-to-register-a-sysctl-mount-point
+++ a/include/linux/sysctl.h
@@ -209,6 +209,8 @@ extern int sysctl_init(void);
extern void __register_sysctl_init(const char *path, struct ctl_table *table,
const char *table_name);
#define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table)
+extern struct ctl_table_header *register_sysctl_mount_point(const char *path);
+
void do_sysctl_args(void);
extern int pwrsw_enabled;
@@ -223,6 +225,11 @@ static inline struct ctl_table_header *r
{
return NULL;
}
+
+static inline struct sysctl_header *register_sysctl_mount_point(const char *path)
+{
+ return NULL;
+}
static inline struct ctl_table_header *register_sysctl_paths(
const struct ctl_path *path, struct ctl_table *table)
_
Patches currently in -mm which might be from mcgrof@xxxxxxxxxx are
zram-use-attribute_groups.patch
hpet-simplify-subdirectory-registration-with-register_sysctl.patch
i915-simplify-subdirectory-registration-with-register_sysctl.patch
macintosh-mac_hidc-simplify-subdirectory-registration-with-register_sysctl.patch
ocfs2-simplify-subdirectory-registration-with-register_sysctl.patch
test_sysctl-simplify-subdirectory-registration-with-register_sysctl.patch
inotify-simplify-subdirectory-registration-with-register_sysctl-fix.patch
cdrom-simplify-subdirectory-registration-with-register_sysctl.patch
sysctl-add-helper-to-register-a-sysctl-mount-point.patch
fs-move-binfmt_misc-sysctl-to-its-own-file.patch
sysctl-share-unsigned-long-const-values.patch
