[Ocfs2-devel] [PATCH 00/13] sysctl: spring cleaning

[Ocfs2-devel] [PATCH 00/13] sysctl: spring cleaning

[Luis Chamberlain]

Me and Xiaoming are working on some kernel/sysctl.c spring cleaning.
During a recent linux-next merge conflict it became clear that
the kitchen sink on kernel/sysctl.c creates too many conflicts,
and so we need to do away with stuffing everyone's knobs on this
one file.

This is part of that work. This is not expected to get merged yet, but
since our delta is pretty considerable at this point, we need to piece
meal this and collect reviews for what we have so far. This follows up
on some of his recent work.

This series focuses on a new helper to deal with subdirectories and
empty subdirectories. The terminology that we will embrace will be
that things like "fs", "kernel", "debug" are based directories, and
directories underneath this are subdirectories.

In this case, the cleanup ends up also trimming the amount of
code we have for sysctls.

If this seems reasonable we'll kdocify this a bit too.

This code has been boot tested without issues, and I'm letting 0day do
its thing to test against many kconfig builds. If you however spot
any issues please let us know.

Luis Chamberlain (9):
  sysctl: add new register_sysctl_subdir() helper
  cdrom: use new sysctl subdir helper register_sysctl_subdir()
  hpet: use new sysctl subdir helper register_sysctl_subdir()
  i915: use new sysctl subdir helper register_sysctl_subdir()
  macintosh/mac_hid.c: use new sysctl subdir helper
    register_sysctl_subdir()
  ocfs2: use new sysctl subdir helper register_sysctl_subdir()
  test_sysctl: use new sysctl subdir helper register_sysctl_subdir()
  sysctl: add helper to register empty subdir
  fs: move binfmt_misc sysctl to its own file

Xiaoming Ni (4):
  inotify: simplify sysctl declaration with register_sysctl_subdir()
  firmware_loader: simplify sysctl declaration with
    register_sysctl_subdir()
  eventpoll: simplify sysctl declaration with register_sysctl_subdir()
  random: simplify sysctl declaration with register_sysctl_subdir()

 drivers/base/firmware_loader/fallback.c       |  4 +
 drivers/base/firmware_loader/fallback.h       | 11 +++
 drivers/base/firmware_loader/fallback_table.c | 22 ++++-
 drivers/cdrom/cdrom.c                         | 23 +----
 drivers/char/hpet.c                           | 22 +----
 drivers/char/random.c                         | 14 +++-
 drivers/gpu/drm/i915/i915_perf.c              | 22 +----
 drivers/macintosh/mac_hid.c                   | 25 +-----
 fs/binfmt_misc.c                              |  1 +
 fs/eventpoll.c                                | 10 ++-
 fs/notify/inotify/inotify_user.c              | 11 ++-
 fs/ocfs2/stackglue.c                          | 27 +-----
 include/linux/inotify.h                       |  3 -
 include/linux/poll.h                          |  2 -
 include/linux/sysctl.h                        | 21 ++++-
 kernel/sysctl.c                               | 84 +++++++++++--------
 lib/test_sysctl.c                             | 23 +----
 17 files changed, 144 insertions(+), 181 deletions(-)

-- 
2.26.2

[Ocfs2-devel] [PATCH 01/13] sysctl: add new register_sysctl_subdir() helper

[Luis Chamberlain]

Often enough all we need to do is create a subdirectory so that
we can stuff sysctls underneath it. However, *if* that directory
was already created early on the boot sequence we really have no
need to use the full boiler plate code for it, we can just use
local variables to help us guide sysctl to place the new leaf files.

So use a helper to do precisely this.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 include/linux/sysctl.h | 11 +++++++++++
 kernel/sysctl.c        | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index ddaa06ddd852..58bc978d4f03 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -205,6 +205,9 @@ void unregister_sysctl_table(struct ctl_table_header * table);
 extern int sysctl_init(void);
 extern void register_sysctl_init(const char *path, struct ctl_table *table,
 				 const char *table_name);
+extern struct ctl_table_header *register_sysctl_subdir(const char *base,
+						       const char *subdir,
+						       struct ctl_table *table);
 void do_sysctl_args(void);
 
 extern int pwrsw_enabled;
@@ -223,6 +226,14 @@ static inline struct ctl_table_header *register_sysctl_table(struct ctl_table *
 	return NULL;
 }
 
+static
+inline struct ctl_table_header *register_sysctl_subdir(const char *base,
+						       const char *subdir,
+						       struct ctl_table *table)
+{
+	return NULL;
+}
+
 static inline struct ctl_table_header *register_sysctl_paths(
 			const struct ctl_path *path, struct ctl_table *table)
 {
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 008ac0576ae5..04ff032f2863 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -3195,6 +3195,43 @@ void __init register_sysctl_init(const char *path, struct ctl_table *table,
 	}
 	kmemleak_not_leak(hdr);
 }
+
+struct ctl_table_header *register_sysctl_subdir(const char *base,
+						const char *subdir,
+						struct ctl_table *table)
+{
+	struct ctl_table_header *hdr = NULL;
+	struct ctl_table subdir_table[] = {
+		{
+			.procname	= subdir,
+			.mode		= 0555,
+			.child		= table,
+		},
+		{ }
+	};
+	struct ctl_table base_table[] = {
+		{
+			.procname	= base,
+			.mode		= 0555,
+			.child		= subdir_table,
+		},
+		{ }
+	};
+
+	if (!table->procname)
+		goto out;
+
+	hdr = register_sysctl_table(base_table);
+	if (unlikely(!hdr)) {
+		pr_err("failed when creating subdirectory sysctl %s/%s/%s\n",
+		       base, subdir, table->procname);
+		goto out;
+	}
+	kmemleak_not_leak(hdr);
+out:
+	return hdr;
+}
+EXPORT_SYMBOL_GPL(register_sysctl_subdir);
 #endif /* CONFIG_SYSCTL */
 /*
  * No sense putting this after each symbol definition, twice,
-- 
2.26.2

[Ocfs2-devel] [PATCH 01/13] sysctl: add new register_sysctl_subdir() helper

[Jani Nikula]

On Fri, 29 May 2020, Luis Chamberlain <mcgrof@kernel.org> wrote:
> Often enough all we need to do is create a subdirectory so that
> we can stuff sysctls underneath it. However, *if* that directory
> was already created early on the boot sequence we really have no
> need to use the full boiler plate code for it, we can just use
> local variables to help us guide sysctl to place the new leaf files.

I find it hard to figure out the lifetime requirements for the tables
passed in; when it's okay to use local variables and when you need
longer lifetimes. It's not documented, everyone appears to be using
static tables for this. It's far from obvious.

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Graphics Center

[Ocfs2-devel] [PATCH 01/13] sysctl: add new register_sysctl_subdir() helper

[Luis Chamberlain]

On Fri, May 29, 2020 at 11:13:21AM +0300, Jani Nikula wrote:
> On Fri, 29 May 2020, Luis Chamberlain <mcgrof@kernel.org> wrote:
> > Often enough all we need to do is create a subdirectory so that
> > we can stuff sysctls underneath it. However, *if* that directory
> > was already created early on the boot sequence we really have no
> > need to use the full boiler plate code for it, we can just use
> > local variables to help us guide sysctl to place the new leaf files.
> 
> I find it hard to figure out the lifetime requirements for the tables
> passed in; when it's okay to use local variables and when you need
> longer lifetimes. It's not documented, everyone appears to be using
> static tables for this. It's far from obvious.

I agree 2000% that it is not obvious. What made me consider it was that
I *knew* that the base directory would already exist, so it wouldn't
make sense for the code to rely on earlier parts of a table if part
of the hierarchy already existed.

In fact, a *huge* part of the due dilligence on this and futre series
on this cleanup will be to be 100% sure that the base path is already
created. And so this use is obviously dangerous, you just *need* to
know that the base path is created before.

Non-posted changes also deal with link order to help address this
in other places, given that link order controls how *initcalls()
(early_initcall(), late_initcall(), etc) are ordered if you have
multiple of these.

I had a link order series long ago which augmented our ability to make
things clearer at a link order. Eventually I believe this will become
more important, specially as we end up wanting to async more code.

For now, we can only rely on manual code inspection for ensuring
proper ordering. Part of the implicit aspects of this cleanup is
to slowly make these things clearer for each base path.

So... the "fs" base path will actually end up being created in
fs/sysctl.c after we are *fully* done with the fs sysctl cleanups.

  Luis

[Ocfs2-devel] [PATCH 01/13] sysctl: add new register_sysctl_subdir() helper

[Eric W. Biederman]

Luis Chamberlain <mcgrof@kernel.org> writes:

> Often enough all we need to do is create a subdirectory so that
> we can stuff sysctls underneath it. However, *if* that directory
> was already created early on the boot sequence we really have no
> need to use the full boiler plate code for it, we can just use
> local variables to help us guide sysctl to place the new leaf files.
>
> So use a helper to do precisely this.

Reset restart.  This is patch is total nonsense.

- You are using register_sysctl_table which as I believe I have
  mentioned is a deprecated compatibility wrapper.  The point of
  spring house cleaning is to get off of the deprecated functions
  isn't it?

- You are using the old nasty form for creating directories instead
  of just passing in a path.

- None of this is even remotely necessary.  The directories
  are created automatically if you just register their entries.

Eric

[Ocfs2-devel] [PATCH 01/13] sysctl: add new register_sysctl_subdir() helper

[Eric W. Biederman]

ebiederm at xmission.com (Eric W. Biederman) writes:

> Luis Chamberlain <mcgrof@kernel.org> writes:
>
>> Often enough all we need to do is create a subdirectory so that
>> we can stuff sysctls underneath it. However, *if* that directory
>> was already created early on the boot sequence we really have no
>> need to use the full boiler plate code for it, we can just use
>> local variables to help us guide sysctl to place the new leaf files.
>>
>> So use a helper to do precisely this.
>
> Reset restart.  This is patch is total nonsense.
>
> - You are using register_sysctl_table which as I believe I have
>   mentioned is a deprecated compatibility wrapper.  The point of
>   spring house cleaning is to get off of the deprecated functions
>   isn't it?
>
> - You are using the old nasty form for creating directories instead
>   of just passing in a path.
>
> - None of this is even remotely necessary.  The directories
>   are created automatically if you just register their entries.

Oh.  *blink*  The poor naming threw me off.

This is a clumsy and poorly named version of register_sysctl();

Yes. This change is totally unnecessary.

Eric

[Ocfs2-devel] [PATCH 02/13] cdrom: use new sysctl subdir helper register_sysctl_subdir()

[Luis Chamberlain]

This simplifies the code considerably. The following coccinelle
SmPL grammar rule was used to transform this code.

// pycocci sysctl-subdir.cocci drivers/cdrom/cdrom.c

@c1@
expression E1;
identifier subdir, sysctls;
@@

static struct ctl_table subdir[] = {
	{
		.procname = E1,
		.maxlen = 0,
		.mode = 0555,
		.child = sysctls,
	},
	{ }
};

@c2@
identifier c1.subdir;

expression E2;
identifier base;
@@

static struct ctl_table base[] = {
	{
		.procname = E2,
		.maxlen = 0,
		.mode = 0555,
		.child = subdir,
	},
	{ }
};

@c3@
identifier c2.base;
identifier header;
@@

header = register_sysctl_table(base);

@r1 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.subdir, c1.sysctls;
@@

-static struct ctl_table subdir[] = {
-	{
-		.procname = E1,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = sysctls,
-	},
-	{ }
-};

@r2 depends on c1 && c2 && c3@
identifier c1.subdir;

expression c2.E2;
identifier c2.base;
@@
-static struct ctl_table base[] = {
-	{
-		.procname = E2,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = subdir,
-	},
-	{ }
-};

@r3 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.sysctls;
expression c2.E2;
identifier c2.base;
identifier c3.header;
@@

header =
-register_sysctl_table(base);
+register_sysctl_subdir(E2, E1, sysctls);

Generated-by: Coccinelle SmPL
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/cdrom/cdrom.c | 23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index a0a7ae705de8..3c638f464cef 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -3719,26 +3719,6 @@ static struct ctl_table cdrom_table[] = {
 	{ }
 };
 
-static struct ctl_table cdrom_cdrom_table[] = {
-	{
-		.procname	= "cdrom",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= cdrom_table,
-	},
-	{ }
-};
-
-/* Make sure that /proc/sys/dev is there */
-static struct ctl_table cdrom_root_table[] = {
-	{
-		.procname	= "dev",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= cdrom_cdrom_table,
-	},
-	{ }
-};
 static struct ctl_table_header *cdrom_sysctl_header;
 
 static void cdrom_sysctl_register(void)
@@ -3748,7 +3728,8 @@ static void cdrom_sysctl_register(void)
 	if (!atomic_add_unless(&initialized, 1, 1))
 		return;
 
-	cdrom_sysctl_header = register_sysctl_table(cdrom_root_table);
+	cdrom_sysctl_header = register_sysctl_subdir("dev", "cdrom",
+						     cdrom_table);
 
 	/* set the defaults */
 	cdrom_sysctl_settings.autoclose = autoclose;
-- 
2.26.2

[Ocfs2-devel] [PATCH 02/13] cdrom: use new sysctl subdir helper register_sysctl_subdir()

[Eric W. Biederman]

Luis Chamberlain <mcgrof@kernel.org> writes:

> This simplifies the code considerably. The following coccinelle

With register_sysctl the code would read:

	cdrom_sysctl_header = register_sysctl("dev/cdrom", cdrom_table);

Please go that direction.  Thank you.

Eric

[Ocfs2-devel] [PATCH 03/13] hpet: use new sysctl subdir helper register_sysctl_subdir()

[Luis Chamberlain]

This simplifies the code considerably. The following coccinelle
SmPL grammar rule was used to transform this code.

// pycocci sysctl-subdir.cocci drivers/char/hpet.c

@c1@
expression E1;
identifier subdir, sysctls;
@@

static struct ctl_table subdir[] = {
	{
		.procname = E1,
		.maxlen = 0,
		.mode = 0555,
		.child = sysctls,
	},
	{ }
};

@c2@
identifier c1.subdir;

expression E2;
identifier base;
@@

static struct ctl_table base[] = {
	{
		.procname = E2,
		.maxlen = 0,
		.mode = 0555,
		.child = subdir,
	},
	{ }
};

@c3@
identifier c2.base;
identifier header;
@@

header = register_sysctl_table(base);

@r1 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.subdir, c1.sysctls;
@@

-static struct ctl_table subdir[] = {
-	{
-		.procname = E1,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = sysctls,
-	},
-	{ }
-};

@r2 depends on c1 && c2 && c3@
identifier c1.subdir;

expression c2.E2;
identifier c2.base;
@@
-static struct ctl_table base[] = {
-	{
-		.procname = E2,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = subdir,
-	},
-	{ }
-};

@r3 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.sysctls;
expression c2.E2;
identifier c2.base;
identifier c3.header;
@@

header =
-register_sysctl_table(base);
+register_sysctl_subdir(E2, E1, sysctls);

Generated-by: Coccinelle SmPL

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/char/hpet.c | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index ed3b7dab678d..169c970d5ff8 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -746,26 +746,6 @@ static struct ctl_table hpet_table[] = {
 	{}
 };
 
-static struct ctl_table hpet_root[] = {
-	{
-	 .procname = "hpet",
-	 .maxlen = 0,
-	 .mode = 0555,
-	 .child = hpet_table,
-	 },
-	{}
-};
-
-static struct ctl_table dev_root[] = {
-	{
-	 .procname = "dev",
-	 .maxlen = 0,
-	 .mode = 0555,
-	 .child = hpet_root,
-	 },
-	{}
-};
-
 static struct ctl_table_header *sysctl_header;
 
 /*
@@ -1059,7 +1039,7 @@ static int __init hpet_init(void)
 	if (result < 0)
 		return -ENODEV;
 
-	sysctl_header = register_sysctl_table(dev_root);
+	sysctl_header = register_sysctl_subdir("dev", "hpet", hpet_table);
 
 	result = acpi_bus_register_driver(&hpet_acpi_driver);
 	if (result < 0) {
-- 
2.26.2

[Ocfs2-devel] [PATCH 04/13] i915: use new sysctl subdir helper register_sysctl_subdir()

[Luis Chamberlain]

This simplifies the code considerably. The following coccinelle
SmPL grammar rule was used to transform this code.

// pycocci sysctl-subdir.cocci drivers/gpu/drm/i915/i915_perf.c

@c1@
expression E1;
identifier subdir, sysctls;
@@

static struct ctl_table subdir[] = {
	{
		.procname = E1,
		.maxlen = 0,
		.mode = 0555,
		.child = sysctls,
	},
	{ }
};

@c2@
identifier c1.subdir;

expression E2;
identifier base;
@@

static struct ctl_table base[] = {
	{
		.procname = E2,
		.maxlen = 0,
		.mode = 0555,
		.child = subdir,
	},
	{ }
};

@c3@
identifier c2.base;
identifier header;
@@

header = register_sysctl_table(base);

@r1 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.subdir, c1.sysctls;
@@

-static struct ctl_table subdir[] = {
-	{
-		.procname = E1,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = sysctls,
-	},
-	{ }
-};

@r2 depends on c1 && c2 && c3@
identifier c1.subdir;

expression c2.E2;
identifier c2.base;
@@
-static struct ctl_table base[] = {
-	{
-		.procname = E2,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = subdir,
-	},
-	{ }
-};

@r3 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.sysctls;
expression c2.E2;
identifier c2.base;
identifier c3.header;
@@

header =
-register_sysctl_table(base);
+register_sysctl_subdir(E2, E1, sysctls);

Generated-by: Coccinelle SmPL
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/gpu/drm/i915/i915_perf.c | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 665bb076e84d..52509b573794 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -4203,26 +4203,6 @@ static struct ctl_table oa_table[] = {
 	{}
 };
 
-static struct ctl_table i915_root[] = {
-	{
-	 .procname = "i915",
-	 .maxlen = 0,
-	 .mode = 0555,
-	 .child = oa_table,
-	 },
-	{}
-};
-
-static struct ctl_table dev_root[] = {
-	{
-	 .procname = "dev",
-	 .maxlen = 0,
-	 .mode = 0555,
-	 .child = i915_root,
-	 },
-	{}
-};
-
 /**
  * i915_perf_init - initialize i915-perf state on module bind
  * @i915: i915 device instance
@@ -4383,7 +4363,7 @@ static int destroy_config(int id, void *p, void *data)
 
 void i915_perf_sysctl_register(void)
 {
-	sysctl_header = register_sysctl_table(dev_root);
+	sysctl_header = register_sysctl_subdir("dev", "i915", oa_table);
 }
 
 void i915_perf_sysctl_unregister(void)
-- 
2.26.2

[Ocfs2-devel] [PATCH 05/13] macintosh/mac_hid.c: use new sysctl subdir helper register_sysctl_subdir()

[Luis Chamberlain]

This simplifies the code considerably. The following coccinelle
SmPL grammar rule was used to transform this code.

// pycocci sysctl-subdir.cocci drivers/macintosh/mac_hid.c

@c1@
expression E1;
identifier subdir, sysctls;
@@

static struct ctl_table subdir[] = {
	{
		.procname = E1,
		.maxlen = 0,
		.mode = 0555,
		.child = sysctls,
	},
	{ }
};

@c2@
identifier c1.subdir;

expression E2;
identifier base;
@@

static struct ctl_table base[] = {
	{
		.procname = E2,
		.maxlen = 0,
		.mode = 0555,
		.child = subdir,
	},
	{ }
};

@c3@
identifier c2.base;
identifier header;
@@

header = register_sysctl_table(base);

@r1 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.subdir, c1.sysctls;
@@

-static struct ctl_table subdir[] = {
-	{
-		.procname = E1,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = sysctls,
-	},
-	{ }
-};

@r2 depends on c1 && c2 && c3@
identifier c1.subdir;

expression c2.E2;
identifier c2.base;
@@
-static struct ctl_table base[] = {
-	{
-		.procname = E2,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = subdir,
-	},
-	{ }
-};

@r3 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.sysctls;
expression c2.E2;
identifier c2.base;
identifier c3.header;
@@

header =
-register_sysctl_table(base);
+register_sysctl_subdir(E2, E1, sysctls);

Generated-by: Coccinelle SmPL

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/macintosh/mac_hid.c | 25 ++-----------------------
 1 file changed, 2 insertions(+), 23 deletions(-)

diff --git a/drivers/macintosh/mac_hid.c b/drivers/macintosh/mac_hid.c
index 28b8581b44dd..736d0e151716 100644
--- a/drivers/macintosh/mac_hid.c
+++ b/drivers/macintosh/mac_hid.c
@@ -239,33 +239,12 @@ static struct ctl_table mac_hid_files[] = {
 	{ }
 };
 
-/* dir in /proc/sys/dev */
-static struct ctl_table mac_hid_dir[] = {
-	{
-		.procname	= "mac_hid",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= mac_hid_files,
-	},
-	{ }
-};
-
-/* /proc/sys/dev itself, in case that is not there yet */
-static struct ctl_table mac_hid_root_dir[] = {
-	{
-		.procname	= "dev",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= mac_hid_dir,
-	},
-	{ }
-};
-
 static struct ctl_table_header *mac_hid_sysctl_header;
 
 static int __init mac_hid_init(void)
 {
-	mac_hid_sysctl_header = register_sysctl_table(mac_hid_root_dir);
+	mac_hid_sysctl_header = register_sysctl_subdir("dev", "mac_hid",
+						       mac_hid_files);
 	if (!mac_hid_sysctl_header)
 		return -ENOMEM;
 
-- 
2.26.2

[Ocfs2-devel] [PATCH 06/13] ocfs2: use new sysctl subdir helper register_sysctl_subdir()

[Luis Chamberlain]

This simplifies the code considerably. The following coccinelle
SmPL grammar rule was used to transform this code.

// pycocci sysctl-subdir.cocci fs/ocfs2/stackglue.c

@c1@
expression E1;
identifier subdir, sysctls;
@@

static struct ctl_table subdir[] = {
	{
		.procname = E1,
		.maxlen = 0,
		.mode = 0555,
		.child = sysctls,
	},
	{ }
};

@c2@
identifier c1.subdir;

expression E2;
identifier base;
@@

static struct ctl_table base[] = {
	{
		.procname = E2,
		.maxlen = 0,
		.mode = 0555,
		.child = subdir,
	},
	{ }
};

@c3@
identifier c2.base;
identifier header;
@@

header = register_sysctl_table(base);

@r1 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.subdir, c1.sysctls;
@@

-static struct ctl_table subdir[] = {
-	{
-		.procname = E1,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = sysctls,
-	},
-	{ }
-};

@r2 depends on c1 && c2 && c3@
identifier c1.subdir;

expression c2.E2;
identifier c2.base;
@@
-static struct ctl_table base[] = {
-	{
-		.procname = E2,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = subdir,
-	},
-	{ }
-};

@r3 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.sysctls;
expression c2.E2;
identifier c2.base;
identifier c3.header;
@@

header =
-register_sysctl_table(base);
+register_sysctl_subdir(E2, E1, sysctls);

Generated-by: Coccinelle SmPL

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 fs/ocfs2/stackglue.c | 27 ++++-----------------------
 1 file changed, 4 insertions(+), 23 deletions(-)

diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
index a191094694c6..addafced7f59 100644
--- a/fs/ocfs2/stackglue.c
+++ b/fs/ocfs2/stackglue.c
@@ -677,28 +677,8 @@ static struct ctl_table ocfs2_mod_table[] = {
 	},
 	{ }
 };
-
-static struct ctl_table ocfs2_kern_table[] = {
-	{
-		.procname	= "ocfs2",
-		.data		= NULL,
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= ocfs2_mod_table
-	},
-	{ }
-};
-
-static struct ctl_table ocfs2_root_table[] = {
-	{
-		.procname	= "fs",
-		.data		= NULL,
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= ocfs2_kern_table
-	},
-	{ }
-};
+	.data		= NULL,
+	.data		= NULL,
 
 static struct ctl_table_header *ocfs2_table_header;
 
@@ -711,7 +691,8 @@ static int __init ocfs2_stack_glue_init(void)
 {
 	strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
 
-	ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
+	ocfs2_table_header = register_sysctl_subdir("fs", "ocfs2",
+						    ocfs2_mod_table);
 	if (!ocfs2_table_header) {
 		printk(KERN_ERR
 		       "ocfs2 stack glue: unable to register sysctl\n");
-- 
2.26.2

[Ocfs2-devel] [PATCH 06/13] ocfs2: use new sysctl subdir helper register_sysctl_subdir()

[Kees Cook]

On Fri, May 29, 2020 at 07:41:01AM +0000, Luis Chamberlain wrote:
> This simplifies the code considerably. The following coccinelle
> SmPL grammar rule was used to transform this code.
> 
> // pycocci sysctl-subdir.cocci fs/ocfs2/stackglue.c
> 
> @c1@
> expression E1;
> identifier subdir, sysctls;
> @@
> 
> static struct ctl_table subdir[] = {
> 	{
> 		.procname = E1,
> 		.maxlen = 0,
> 		.mode = 0555,
> 		.child = sysctls,
> 	},
> 	{ }
> };
> 
> @c2@
> identifier c1.subdir;
> 
> expression E2;
> identifier base;
> @@
> 
> static struct ctl_table base[] = {
> 	{
> 		.procname = E2,
> 		.maxlen = 0,
> 		.mode = 0555,
> 		.child = subdir,
> 	},
> 	{ }
> };
> 
> @c3@
> identifier c2.base;
> identifier header;
> @@
> 
> header = register_sysctl_table(base);
> 
> @r1 depends on c1 && c2 && c3@
> expression c1.E1;
> identifier c1.subdir, c1.sysctls;
> @@
> 
> -static struct ctl_table subdir[] = {
> -	{
> -		.procname = E1,
> -		.maxlen = 0,
> -		.mode = 0555,
> -		.child = sysctls,
> -	},
> -	{ }
> -};
> 
> @r2 depends on c1 && c2 && c3@
> identifier c1.subdir;
> 
> expression c2.E2;
> identifier c2.base;
> @@
> -static struct ctl_table base[] = {
> -	{
> -		.procname = E2,
> -		.maxlen = 0,
> -		.mode = 0555,
> -		.child = subdir,
> -	},
> -	{ }
> -};
> 
> @r3 depends on c1 && c2 && c3@
> expression c1.E1;
> identifier c1.sysctls;
> expression c2.E2;
> identifier c2.base;
> identifier c3.header;
> @@
> 
> header =
> -register_sysctl_table(base);
> +register_sysctl_subdir(E2, E1, sysctls);
> 
> Generated-by: Coccinelle SmPL
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  fs/ocfs2/stackglue.c | 27 ++++-----------------------
>  1 file changed, 4 insertions(+), 23 deletions(-)
> 
> diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
> index a191094694c6..addafced7f59 100644
> --- a/fs/ocfs2/stackglue.c
> +++ b/fs/ocfs2/stackglue.c
> @@ -677,28 +677,8 @@ static struct ctl_table ocfs2_mod_table[] = {
>  	},
>  	{ }
>  };
> -
> -static struct ctl_table ocfs2_kern_table[] = {
> -	{
> -		.procname	= "ocfs2",
> -		.data		= NULL,
> -		.maxlen		= 0,
> -		.mode		= 0555,
> -		.child		= ocfs2_mod_table
> -	},
> -	{ }
> -};
> -
> -static struct ctl_table ocfs2_root_table[] = {
> -	{
> -		.procname	= "fs",
> -		.data		= NULL,
> -		.maxlen		= 0,
> -		.mode		= 0555,
> -		.child		= ocfs2_kern_table
> -	},
> -	{ }
> -};
> +	.data		= NULL,
> +	.data		= NULL,

The conversion script doesn't like the .data field assignments. ;)

Was this series built with allmodconfig? I would have expected this to
blow up very badly. :)

-- 
Kees Cook

[Ocfs2-devel] [Intel-gfx] [PATCH 06/13] ocfs2: use new sysctl subdir helper register_sysctl_subdir()

[Luis Chamberlain]

On Fri, May 29, 2020 at 01:23:19AM -0700, Kees Cook wrote:
> On Fri, May 29, 2020 at 07:41:01AM +0000, Luis Chamberlain wrote:
> > This simplifies the code considerably. The following coccinelle
> > SmPL grammar rule was used to transform this code.
> > 
> > // pycocci sysctl-subdir.cocci fs/ocfs2/stackglue.c
> > 
> > @c1@
> > expression E1;
> > identifier subdir, sysctls;
> > @@
> > 
> > static struct ctl_table subdir[] = {
> > 	{
> > 		.procname = E1,
> > 		.maxlen = 0,
> > 		.mode = 0555,
> > 		.child = sysctls,
> > 	},
> > 	{ }
> > };
> > 
> > @c2@
> > identifier c1.subdir;
> > 
> > expression E2;
> > identifier base;
> > @@
> > 
> > static struct ctl_table base[] = {
> > 	{
> > 		.procname = E2,
> > 		.maxlen = 0,
> > 		.mode = 0555,
> > 		.child = subdir,
> > 	},
> > 	{ }
> > };
> > 
> > @c3@
> > identifier c2.base;
> > identifier header;
> > @@
> > 
> > header = register_sysctl_table(base);
> > 
> > @r1 depends on c1 && c2 && c3@
> > expression c1.E1;
> > identifier c1.subdir, c1.sysctls;
> > @@
> > 
> > -static struct ctl_table subdir[] = {
> > -	{
> > -		.procname = E1,
> > -		.maxlen = 0,
> > -		.mode = 0555,
> > -		.child = sysctls,
> > -	},
> > -	{ }
> > -};
> > 
> > @r2 depends on c1 && c2 && c3@
> > identifier c1.subdir;
> > 
> > expression c2.E2;
> > identifier c2.base;
> > @@
> > -static struct ctl_table base[] = {
> > -	{
> > -		.procname = E2,
> > -		.maxlen = 0,
> > -		.mode = 0555,
> > -		.child = subdir,
> > -	},
> > -	{ }
> > -};
> > 
> > @r3 depends on c1 && c2 && c3@
> > expression c1.E1;
> > identifier c1.sysctls;
> > expression c2.E2;
> > identifier c2.base;
> > identifier c3.header;
> > @@
> > 
> > header =
> > -register_sysctl_table(base);
> > +register_sysctl_subdir(E2, E1, sysctls);
> > 
> > Generated-by: Coccinelle SmPL
> > 
> > Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> > ---
> >  fs/ocfs2/stackglue.c | 27 ++++-----------------------
> >  1 file changed, 4 insertions(+), 23 deletions(-)
> > 
> > diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
> > index a191094694c6..addafced7f59 100644
> > --- a/fs/ocfs2/stackglue.c
> > +++ b/fs/ocfs2/stackglue.c
> > @@ -677,28 +677,8 @@ static struct ctl_table ocfs2_mod_table[] = {
> >  	},
> >  	{ }
> >  };
> > -
> > -static struct ctl_table ocfs2_kern_table[] = {
> > -	{
> > -		.procname	= "ocfs2",
> > -		.data		= NULL,
> > -		.maxlen		= 0,
> > -		.mode		= 0555,
> > -		.child		= ocfs2_mod_table
> > -	},
> > -	{ }
> > -};
> > -
> > -static struct ctl_table ocfs2_root_table[] = {
> > -	{
> > -		.procname	= "fs",
> > -		.data		= NULL,
> > -		.maxlen		= 0,
> > -		.mode		= 0555,
> > -		.child		= ocfs2_kern_table
> > -	},
> > -	{ }
> > -};
> > +	.data		= NULL,
> > +	.data		= NULL,
> 
> The conversion script doesn't like the .data field assignments. ;)
> 
> Was this series built with allmodconfig? I would have expected this to
> blow up very badly. :)

Yikes, sense, you're right. Nope, I left the random config tests to
0day. Will fix, thanks!

  Luis

[Ocfs2-devel] [Intel-gfx] [PATCH 06/13] ocfs2: use new sysctl subdir helper register_sysctl_subdir()

[Kees Cook]

On Fri, May 29, 2020 at 11:49:12AM +0000, Luis Chamberlain wrote:
> Yikes, sense, you're right. Nope, I left the random config tests to
> 0day. Will fix, thanks!

Yeah, I do the same for randconfig, but I always do an "allmodconfig"
build before sending stuff. It's a good smoke test.

-- 
Kees Cook

[Ocfs2-devel] [PATCH 07/13] test_sysctl: use new sysctl subdir helper register_sysctl_subdir()

[Luis Chamberlain]

This simplifies the code considerably. The following coccinelle
SmPL grammar rule was used to transform this code.

// pycocci sysctl-subdir.cocci lib/test_sysctl.c

@c1@
expression E1;
identifier subdir, sysctls;
@@

static struct ctl_table subdir[] = {
	{
		.procname = E1,
		.maxlen = 0,
		.mode = 0555,
		.child = sysctls,
	},
	{ }
};

@c2@
identifier c1.subdir;

expression E2;
identifier base;
@@

static struct ctl_table base[] = {
	{
		.procname = E2,
		.maxlen = 0,
		.mode = 0555,
		.child = subdir,
	},
	{ }
};

@c3@
identifier c2.base;
identifier header;
@@

header = register_sysctl_table(base);

@r1 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.subdir, c1.sysctls;
@@

-static struct ctl_table subdir[] = {
-	{
-		.procname = E1,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = sysctls,
-	},
-	{ }
-};

@r2 depends on c1 && c2 && c3@
identifier c1.subdir;

expression c2.E2;
identifier c2.base;
@@
-static struct ctl_table base[] = {
-	{
-		.procname = E2,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = subdir,
-	},
-	{ }
-};

@r3 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.sysctls;
expression c2.E2;
identifier c2.base;
identifier c3.header;
@@

header =
-register_sysctl_table(base);
+register_sysctl_subdir(E2, E1, sysctls);

Generated-by: Coccinelle SmPL
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 lib/test_sysctl.c | 23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c
index 84eaae22d3a6..b17581307756 100644
--- a/lib/test_sysctl.c
+++ b/lib/test_sysctl.c
@@ -128,26 +128,6 @@ static struct ctl_table test_table[] = {
 	{ }
 };
 
-static struct ctl_table test_sysctl_table[] = {
-	{
-		.procname	= "test_sysctl",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= test_table,
-	},
-	{ }
-};
-
-static struct ctl_table test_sysctl_root_table[] = {
-	{
-		.procname	= "debug",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= test_sysctl_table,
-	},
-	{ }
-};
-
 static struct ctl_table_header *test_sysctl_header;
 
 static int __init test_sysctl_init(void)
@@ -155,7 +135,8 @@ static int __init test_sysctl_init(void)
 	test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL);
 	if (!test_data.bitmap_0001)
 		return -ENOMEM;
-	test_sysctl_header = register_sysctl_table(test_sysctl_root_table);
+	test_sysctl_header = register_sysctl_subdir("debug", "test_sysctl",
+						    test_table);
 	if (!test_sysctl_header) {
 		kfree(test_data.bitmap_0001);
 		return -ENOMEM;
-- 
2.26.2

[Ocfs2-devel] [PATCH 08/13] inotify: simplify sysctl declaration with register_sysctl_subdir()

[Luis Chamberlain]

From: Xiaoming Ni <nixiaoming@huawei.com>

move inotify_user sysctl to inotify_user.c and use the new
register_sysctl_subdir() helper.

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 fs/notify/inotify/inotify_user.c | 11 ++++++++++-
 include/linux/inotify.h          |  3 ---
 kernel/sysctl.c                  | 11 -----------
 3 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index f88bbcc9efeb..64859fbf8463 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -46,7 +46,7 @@ struct kmem_cache *inotify_inode_mark_cachep __read_mostly;
 
 #include <linux/sysctl.h>
 
-struct ctl_table inotify_table[] = {
+static struct ctl_table inotify_table[] = {
 	{
 		.procname	= "max_user_instances",
 		.data		= &init_user_ns.ucount_max[UCOUNT_INOTIFY_INSTANCES],
@@ -73,6 +73,14 @@ struct ctl_table inotify_table[] = {
 	},
 	{ }
 };
+
+static void __init inotify_sysctls_init(void)
+{
+	register_sysctl_subdir("fs", "inotify", inotify_table);
+}
+
+#else
+#define inotify_sysctls_init() do { } while (0)
 #endif /* CONFIG_SYSCTL */
 
 static inline __u32 inotify_arg_to_mask(u32 arg)
@@ -826,6 +834,7 @@ static int __init inotify_user_setup(void)
 	inotify_max_queued_events = 16384;
 	init_user_ns.ucount_max[UCOUNT_INOTIFY_INSTANCES] = 128;
 	init_user_ns.ucount_max[UCOUNT_INOTIFY_WATCHES] = 8192;
+	inotify_sysctls_init();
 
 	return 0;
 }
diff --git a/include/linux/inotify.h b/include/linux/inotify.h
index 6a24905f6e1e..8d20caa1b268 100644
--- a/include/linux/inotify.h
+++ b/include/linux/inotify.h
@@ -7,11 +7,8 @@
 #ifndef _LINUX_INOTIFY_H
 #define _LINUX_INOTIFY_H
 
-#include <linux/sysctl.h>
 #include <uapi/linux/inotify.h>
 
-extern struct ctl_table inotify_table[]; /* for sysctl */
-
 #define ALL_INOTIFY_BITS (IN_ACCESS | IN_MODIFY | IN_ATTRIB | IN_CLOSE_WRITE | \
 			  IN_CLOSE_NOWRITE | IN_OPEN | IN_MOVED_FROM | \
 			  IN_MOVED_TO | IN_CREATE | IN_DELETE | \
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 04ff032f2863..30c2d521502a 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -123,10 +123,6 @@ static const int maxolduid = 65535;
 static int ngroups_max = NGROUPS_MAX;
 static const int cap_last_cap = CAP_LAST_CAP;
 
-#ifdef CONFIG_INOTIFY_USER
-#include <linux/inotify.h>
-#endif
-
 #ifdef CONFIG_PROC_SYSCTL
 
 /**
@@ -3012,13 +3008,6 @@ static struct ctl_table fs_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 #endif
-#ifdef CONFIG_INOTIFY_USER
-	{
-		.procname	= "inotify",
-		.mode		= 0555,
-		.child		= inotify_table,
-	},
-#endif	
 #ifdef CONFIG_EPOLL
 	{
 		.procname	= "epoll",
-- 
2.26.2

[Ocfs2-devel] [PATCH 09/13] firmware_loader: simplify sysctl declaration with register_sysctl_subdir()

[Luis Chamberlain]

From: Xiaoming Ni <nixiaoming@huawei.com>

Move the firmware config sysctl table to fallback_table.c and use the
new register_sysctl_subdir() helper. This removes the clutter from
kernel/sysctl.c.

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/base/firmware_loader/fallback.c       |  4 ++++
 drivers/base/firmware_loader/fallback.h       | 11 ++++++++++
 drivers/base/firmware_loader/fallback_table.c | 22 +++++++++++++++++--
 include/linux/sysctl.h                        |  1 -
 kernel/sysctl.c                               |  7 ------
 5 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
index d9ac7296205e..8190653ae9a3 100644
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -200,12 +200,16 @@ static struct class firmware_class = {
 
 int register_sysfs_loader(void)
 {
+	int ret = register_firmware_config_sysctl();
+	if (ret != 0)
+		return ret;
 	return class_register(&firmware_class);
 }
 
 void unregister_sysfs_loader(void)
 {
 	class_unregister(&firmware_class);
+	unregister_firmware_config_sysctl();
 }
 
 static ssize_t firmware_loading_show(struct device *dev,
diff --git a/drivers/base/firmware_loader/fallback.h b/drivers/base/firmware_loader/fallback.h
index 06f4577733a8..7d2cb5f6ceb8 100644
--- a/drivers/base/firmware_loader/fallback.h
+++ b/drivers/base/firmware_loader/fallback.h
@@ -42,6 +42,17 @@ void fw_fallback_set_default_timeout(void);
 
 int register_sysfs_loader(void);
 void unregister_sysfs_loader(void);
+#ifdef CONFIG_SYSCTL
+extern int register_firmware_config_sysctl(void);
+extern void unregister_firmware_config_sysctl(void);
+#else
+static inline int register_firmware_config_sysctl(void)
+{
+	return 0;
+}
+static inline void unregister_firmware_config_sysctl(void) { }
+#endif /* CONFIG_SYSCTL */
+
 #else /* CONFIG_FW_LOADER_USER_HELPER */
 static inline int firmware_fallback_sysfs(struct firmware *fw, const char *name,
 					  struct device *device,
diff --git a/drivers/base/firmware_loader/fallback_table.c b/drivers/base/firmware_loader/fallback_table.c
index 46a731dede6f..4234aa5ee5df 100644
--- a/drivers/base/firmware_loader/fallback_table.c
+++ b/drivers/base/firmware_loader/fallback_table.c
@@ -24,7 +24,7 @@ struct firmware_fallback_config fw_fallback_config = {
 EXPORT_SYMBOL_NS_GPL(fw_fallback_config, FIRMWARE_LOADER_PRIVATE);
 
 #ifdef CONFIG_SYSCTL
-struct ctl_table firmware_config_table[] = {
+static struct ctl_table firmware_config_table[] = {
 	{
 		.procname	= "force_sysfs_fallback",
 		.data		= &fw_fallback_config.force_sysfs_fallback,
@@ -45,4 +45,22 @@ struct ctl_table firmware_config_table[] = {
 	},
 	{ }
 };
-#endif
+
+static struct ctl_table_header *hdr;
+int register_firmware_config_sysctl(void)
+{
+	if (hdr)
+		return -EEXIST;
+	hdr = register_sysctl_subdir("kernel", "firmware_config",
+				     firmware_config_table);
+	if (!hdr)
+		return -ENOMEM;
+	return 0;
+}
+
+void unregister_firmware_config_sysctl(void)
+{
+	if (hdr)
+		unregister_sysctl_table(hdr);
+}
+#endif /* CONFIG_SYSCTL */
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 58bc978d4f03..aa01f54d0442 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -217,7 +217,6 @@ extern int no_unaligned_warning;
 
 extern struct ctl_table sysctl_mount_point[];
 extern struct ctl_table random_table[];
-extern struct ctl_table firmware_config_table[];
 extern struct ctl_table epoll_table[];
 
 #else /* CONFIG_SYSCTL */
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 30c2d521502a..e007375c8a11 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2088,13 +2088,6 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0555,
 		.child		= usermodehelper_table,
 	},
-#ifdef CONFIG_FW_LOADER_USER_HELPER
-	{
-		.procname	= "firmware_config",
-		.mode		= 0555,
-		.child		= firmware_config_table,
-	},
-#endif
 	{
 		.procname	= "overflowuid",
 		.data		= &overflowuid,
-- 
2.26.2

[Ocfs2-devel] [PATCH 09/13] firmware_loader: simplify sysctl declaration with register_sysctl_subdir()

[Greg KH]

On Fri, May 29, 2020 at 07:41:04AM +0000, Luis Chamberlain wrote:
> From: Xiaoming Ni <nixiaoming@huawei.com>
> 
> Move the firmware config sysctl table to fallback_table.c and use the
> new register_sysctl_subdir() helper. This removes the clutter from
> kernel/sysctl.c.
> 
> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  drivers/base/firmware_loader/fallback.c       |  4 ++++
>  drivers/base/firmware_loader/fallback.h       | 11 ++++++++++
>  drivers/base/firmware_loader/fallback_table.c | 22 +++++++++++++++++--
>  include/linux/sysctl.h                        |  1 -
>  kernel/sysctl.c                               |  7 ------
>  5 files changed, 35 insertions(+), 10 deletions(-)

So it now takes more lines than the old stuff?  :(

> 
> diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
> index d9ac7296205e..8190653ae9a3 100644
> --- a/drivers/base/firmware_loader/fallback.c
> +++ b/drivers/base/firmware_loader/fallback.c
> @@ -200,12 +200,16 @@ static struct class firmware_class = {
>  
>  int register_sysfs_loader(void)
>  {
> +	int ret = register_firmware_config_sysctl();
> +	if (ret != 0)
> +		return ret;

checkpatch :(

>  	return class_register(&firmware_class);

And if that fails?

>  }
>  
>  void unregister_sysfs_loader(void)
>  {
>  	class_unregister(&firmware_class);
> +	unregister_firmware_config_sysctl();
>  }
>  
>  static ssize_t firmware_loading_show(struct device *dev,
> diff --git a/drivers/base/firmware_loader/fallback.h b/drivers/base/firmware_loader/fallback.h
> index 06f4577733a8..7d2cb5f6ceb8 100644
> --- a/drivers/base/firmware_loader/fallback.h
> +++ b/drivers/base/firmware_loader/fallback.h
> @@ -42,6 +42,17 @@ void fw_fallback_set_default_timeout(void);
>  
>  int register_sysfs_loader(void);
>  void unregister_sysfs_loader(void);
> +#ifdef CONFIG_SYSCTL
> +extern int register_firmware_config_sysctl(void);
> +extern void unregister_firmware_config_sysctl(void);
> +#else
> +static inline int register_firmware_config_sysctl(void)
> +{
> +	return 0;
> +}
> +static inline void unregister_firmware_config_sysctl(void) { }
> +#endif /* CONFIG_SYSCTL */
> +
>  #else /* CONFIG_FW_LOADER_USER_HELPER */
>  static inline int firmware_fallback_sysfs(struct firmware *fw, const char *name,
>  					  struct device *device,
> diff --git a/drivers/base/firmware_loader/fallback_table.c b/drivers/base/firmware_loader/fallback_table.c
> index 46a731dede6f..4234aa5ee5df 100644
> --- a/drivers/base/firmware_loader/fallback_table.c
> +++ b/drivers/base/firmware_loader/fallback_table.c
> @@ -24,7 +24,7 @@ struct firmware_fallback_config fw_fallback_config = {
>  EXPORT_SYMBOL_NS_GPL(fw_fallback_config, FIRMWARE_LOADER_PRIVATE);
>  
>  #ifdef CONFIG_SYSCTL
> -struct ctl_table firmware_config_table[] = {
> +static struct ctl_table firmware_config_table[] = {
>  	{
>  		.procname	= "force_sysfs_fallback",
>  		.data		= &fw_fallback_config.force_sysfs_fallback,
> @@ -45,4 +45,22 @@ struct ctl_table firmware_config_table[] = {
>  	},
>  	{ }
>  };
> -#endif
> +
> +static struct ctl_table_header *hdr;
> +int register_firmware_config_sysctl(void)
> +{
> +	if (hdr)
> +		return -EEXIST;

How can hdr be set?

> +	hdr = register_sysctl_subdir("kernel", "firmware_config",
> +				     firmware_config_table);
> +	if (!hdr)
> +		return -ENOMEM;
> +	return 0;
> +}
> +
> +void unregister_firmware_config_sysctl(void)
> +{
> +	if (hdr)
> +		unregister_sysctl_table(hdr);

Why can't unregister_sysctl_table() take a null pointer value?

And what sets 'hdr' (worst name for a static variable) to NULL so that
it knows not to be unregistered again as it looks like
register_firmware_config_sysctl() could be called multiple times.

thanks,

greg k-h

[Ocfs2-devel] [PATCH 09/13] firmware_loader: simplify sysctl declaration with register_sysctl_subdir()

[Xiaoming Ni]

On 2020/5/29 18:26, Greg KH wrote:
> On Fri, May 29, 2020 at 07:41:04AM +0000, Luis Chamberlain wrote:
>> From: Xiaoming Ni <nixiaoming@huawei.com>
>>
>> Move the firmware config sysctl table to fallback_table.c and use the
>> new register_sysctl_subdir() helper. This removes the clutter from
>> kernel/sysctl.c.
>>
>> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
>> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
>> ---
>>   drivers/base/firmware_loader/fallback.c       |  4 ++++
>>   drivers/base/firmware_loader/fallback.h       | 11 ++++++++++
>>   drivers/base/firmware_loader/fallback_table.c | 22 +++++++++++++++++--
>>   include/linux/sysctl.h                        |  1 -
>>   kernel/sysctl.c                               |  7 ------
>>   5 files changed, 35 insertions(+), 10 deletions(-)
> 
> So it now takes more lines than the old stuff?  :(
> 
CONFIG_FW_LOADER = m
Before cleaning, no matter whether ko is loaded or not, the sysctl
interface will be created, but now we need to add register and
unregister interfaces, so the number of lines of code has increased

>>
>> diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
>> index d9ac7296205e..8190653ae9a3 100644
>> --- a/drivers/base/firmware_loader/fallback.c
>> +++ b/drivers/base/firmware_loader/fallback.c
>> @@ -200,12 +200,16 @@ static struct class firmware_class = {
>>   
>>   int register_sysfs_loader(void)
>>   {
>> +	int ret = register_firmware_config_sysctl();
>> +	if (ret != 0)
>> +		return ret;
> 
> checkpatch :(
This is my fault,  thanks for your guidance

> 
>>   	return class_register(&firmware_class);
> 
> And if that fails?
> 
Yes, it is better to call register_firmware_config_sysctl() after 
class_register().
thanks for your guidance.


>>   }
>>   
>>   void unregister_sysfs_loader(void)
>>   {
>>   	class_unregister(&firmware_class);
>> +	unregister_firmware_config_sysctl();
>>   }
>>   
>>   static ssize_t firmware_loading_show(struct device *dev,
>> diff --git a/drivers/base/firmware_loader/fallback.h b/drivers/base/firmware_loader/fallback.h
>> index 06f4577733a8..7d2cb5f6ceb8 100644
>> --- a/drivers/base/firmware_loader/fallback.h
>> +++ b/drivers/base/firmware_loader/fallback.h
>> @@ -42,6 +42,17 @@ void fw_fallback_set_default_timeout(void);
>>   
>>   int register_sysfs_loader(void);
>>   void unregister_sysfs_loader(void);
>> +#ifdef CONFIG_SYSCTL
>> +extern int register_firmware_config_sysctl(void);
>> +extern void unregister_firmware_config_sysctl(void);
>> +#else
>> +static inline int register_firmware_config_sysctl(void)
>> +{
>> +	return 0;
>> +}
>> +static inline void unregister_firmware_config_sysctl(void) { }
>> +#endif /* CONFIG_SYSCTL */
>> +
>>   #else /* CONFIG_FW_LOADER_USER_HELPER */
>>   static inline int firmware_fallback_sysfs(struct firmware *fw, const char *name,
>>   					  struct device *device,
>> diff --git a/drivers/base/firmware_loader/fallback_table.c b/drivers/base/firmware_loader/fallback_table.c
>> index 46a731dede6f..4234aa5ee5df 100644
>> --- a/drivers/base/firmware_loader/fallback_table.c
>> +++ b/drivers/base/firmware_loader/fallback_table.c
>> @@ -24,7 +24,7 @@ struct firmware_fallback_config fw_fallback_config = {
>>   EXPORT_SYMBOL_NS_GPL(fw_fallback_config, FIRMWARE_LOADER_PRIVATE);
>>   
>>   #ifdef CONFIG_SYSCTL
>> -struct ctl_table firmware_config_table[] = {
>> +static struct ctl_table firmware_config_table[] = {
>>   	{
>>   		.procname	= "force_sysfs_fallback",
>>   		.data		= &fw_fallback_config.force_sysfs_fallback,
>> @@ -45,4 +45,22 @@ struct ctl_table firmware_config_table[] = {
>>   	},
>>   	{ }
>>   };
>> -#endif
>> +
>> +static struct ctl_table_header *hdr;
>> +int register_firmware_config_sysctl(void)
>> +{
>> +	if (hdr)
>> +		return -EEXIST;
> 
> How can hdr be set?
> 
It's my mistake, register_firmware_config_sysctl() is not exported,
there will be no repeated calls.
thanks for your guidance.

>> +	hdr = register_sysctl_subdir("kernel", "firmware_config",
>> +				     firmware_config_table);
>> +	if (!hdr)
>> +		return -ENOMEM;
>> +	return 0;
>> +}
>> +
>> +void unregister_firmware_config_sysctl(void)
>> +{
>> +	if (hdr)
>> +		unregister_sysctl_table(hdr);
> 
> Why can't unregister_sysctl_table() take a null pointer value?
Sorry, I didn't notice that the unregister_sysctl_table() already checks
the input parameters.
thanks for your guidance.


> And what sets 'hdr' (worst name for a static variable) to NULL so that
> it knows not to be unregistered again as it looks like
> register_firmware_config_sysctl() could be called multiple times.

How about renaming hdr to firmware_config_sysct_table_header?

+ if (hdr)
+ 	return -EEXIST;
After deleting this code in register_firmware_config_sysctl(), and 
considering register_firmware_config_sysctl() and 
unregister_firmware_config_sysctl() are not exported, whether there is
no need to add  "hdr = NULL;" ?

Thanks
Xiaoming Ni

[Ocfs2-devel] [PATCH 09/13] firmware_loader: simplify sysctl declaration with register_sysctl_subdir()

[Luis Chamberlain]

On Fri, May 29, 2020 at 12:26:13PM +0200, Greg KH wrote:
> On Fri, May 29, 2020 at 07:41:04AM +0000, Luis Chamberlain wrote:
> > From: Xiaoming Ni <nixiaoming@huawei.com>
> > 
> > Move the firmware config sysctl table to fallback_table.c and use the
> > new register_sysctl_subdir() helper. This removes the clutter from
> > kernel/sysctl.c.
> > 
> > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> > Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> > ---
> >  drivers/base/firmware_loader/fallback.c       |  4 ++++
> >  drivers/base/firmware_loader/fallback.h       | 11 ++++++++++
> >  drivers/base/firmware_loader/fallback_table.c | 22 +++++++++++++++++--
> >  include/linux/sysctl.h                        |  1 -
> >  kernel/sysctl.c                               |  7 ------
> >  5 files changed, 35 insertions(+), 10 deletions(-)
> 
> So it now takes more lines than the old stuff?  :(

Pretty much agreed with the other changes, thanks for the review!

But this diff-stat change, indeed, it is unfortunate that we end up
with more code here than before. We'll try to reduce it instead
somehow, however in some cases during this spring-cleaning, since
the goal is to move code from one file to another, it *may* require
more code. So it won't always be negative. But we'll try!

  Luis

[Ocfs2-devel] [PATCH 10/13] eventpoll: simplify sysctl declaration with register_sysctl_subdir()

[Luis Chamberlain]

From: Xiaoming Ni <nixiaoming@huawei.com>

Move epoll_table sysctl to fs/eventpoll.c and remove the
clutter out of kernel/sysctl.c by using register_sysctl_subdir()..

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 fs/eventpoll.c         | 10 +++++++++-
 include/linux/poll.h   |  2 --
 include/linux/sysctl.h |  1 -
 kernel/sysctl.c        |  7 -------
 4 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 12eebcdea9c8..957ebc9700e3 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -299,7 +299,7 @@ static LIST_HEAD(tfile_check_list);
 static long long_zero;
 static long long_max = LONG_MAX;
 
-struct ctl_table epoll_table[] = {
+static struct ctl_table epoll_table[] = {
 	{
 		.procname	= "max_user_watches",
 		.data		= &max_user_watches,
@@ -311,6 +311,13 @@ struct ctl_table epoll_table[] = {
 	},
 	{ }
 };
+
+static void __init epoll_sysctls_init(void)
+{
+	register_sysctl_subdir("fs", "epoll", epoll_table);
+}
+#else
+#define epoll_sysctls_init() do { } while (0)
 #endif /* CONFIG_SYSCTL */
 
 static const struct file_operations eventpoll_fops;
@@ -2422,6 +2429,7 @@ static int __init eventpoll_init(void)
 	/* Allocates slab cache used to allocate "struct eppoll_entry" */
 	pwq_cache = kmem_cache_create("eventpoll_pwq",
 		sizeof(struct eppoll_entry), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL);
+	epoll_sysctls_init();
 
 	return 0;
 }
diff --git a/include/linux/poll.h b/include/linux/poll.h
index 1cdc32b1f1b0..a9e0e1c2d1f2 100644
--- a/include/linux/poll.h
+++ b/include/linux/poll.h
@@ -8,12 +8,10 @@
 #include <linux/wait.h>
 #include <linux/string.h>
 #include <linux/fs.h>
-#include <linux/sysctl.h>
 #include <linux/uaccess.h>
 #include <uapi/linux/poll.h>
 #include <uapi/linux/eventpoll.h>
 
-extern struct ctl_table epoll_table[]; /* for sysctl */
 /* ~832 bytes of stack space used max in sys_select/sys_poll before allocating
    additional memory. */
 #ifdef __clang__
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index aa01f54d0442..e5364b69dd95 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -217,7 +217,6 @@ extern int no_unaligned_warning;
 
 extern struct ctl_table sysctl_mount_point[];
 extern struct ctl_table random_table[];
-extern struct ctl_table epoll_table[];
 
 #else /* CONFIG_SYSCTL */
 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index e007375c8a11..5c116904feb7 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -3001,13 +3001,6 @@ static struct ctl_table fs_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 #endif
-#ifdef CONFIG_EPOLL
-	{
-		.procname	= "epoll",
-		.mode		= 0555,
-		.child		= epoll_table,
-	},
-#endif
 #endif
 	{
 		.procname	= "protected_symlinks",
-- 
2.26.2

[Ocfs2-devel] [PATCH 11/13] random: simplify sysctl declaration with register_sysctl_subdir()

[Luis Chamberlain]

From: Xiaoming Ni <nixiaoming@huawei.com>

Move random_table sysctl from kernel/sysctl.c to drivers/char/random.c
and use register_sysctl_subdir() to help remove the clutter out of
kernel/sysctl.c.

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/char/random.c  | 14 ++++++++++++--
 include/linux/sysctl.h |  1 -
 kernel/sysctl.c        |  5 -----
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index a7cf6aa65908..73fd4b6e9c18 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2101,8 +2101,7 @@ static int proc_do_entropy(struct ctl_table *table, int write,
 }
 
 static int sysctl_poolsize = INPUT_POOL_WORDS * 32;
-extern struct ctl_table random_table[];
-struct ctl_table random_table[] = {
+static struct ctl_table random_table[] = {
 	{
 		.procname	= "poolsize",
 		.data		= &sysctl_poolsize,
@@ -2164,6 +2163,17 @@ struct ctl_table random_table[] = {
 #endif
 	{ }
 };
+
+/*
+ * rand_initialize() is called before sysctl_init(),
+ * so we cannot call register_sysctl_init() in rand_initialize()
+ */
+static int __init random_sysctls_init(void)
+{
+	register_sysctl_subdir("kernel", "random", random_table);
+	return 0;
+}
+device_initcall(random_sysctls_init);
 #endif 	/* CONFIG_SYSCTL */
 
 struct batched_entropy {
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index e5364b69dd95..33a471b56345 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -216,7 +216,6 @@ extern int unaligned_dump_stack;
 extern int no_unaligned_warning;
 
 extern struct ctl_table sysctl_mount_point[];
-extern struct ctl_table random_table[];
 
 #else /* CONFIG_SYSCTL */
 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 5c116904feb7..f9a35325d5d5 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2078,11 +2078,6 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= sysctl_max_threads,
 	},
-	{
-		.procname	= "random",
-		.mode		= 0555,
-		.child		= random_table,
-	},
 	{
 		.procname	= "usermodehelper",
 		.mode		= 0555,
-- 
2.26.2

[Ocfs2-devel] [PATCH 11/13] random: simplify sysctl declaration with register_sysctl_subdir()

[Greg KH]

On Fri, May 29, 2020 at 07:41:06AM +0000, Luis Chamberlain wrote:
> From: Xiaoming Ni <nixiaoming@huawei.com>
> 
> Move random_table sysctl from kernel/sysctl.c to drivers/char/random.c
> and use register_sysctl_subdir() to help remove the clutter out of
> kernel/sysctl.c.
> 
> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  drivers/char/random.c  | 14 ++++++++++++--
>  include/linux/sysctl.h |  1 -
>  kernel/sysctl.c        |  5 -----
>  3 files changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/char/random.c b/drivers/char/random.c
> index a7cf6aa65908..73fd4b6e9c18 100644
> --- a/drivers/char/random.c
> +++ b/drivers/char/random.c
> @@ -2101,8 +2101,7 @@ static int proc_do_entropy(struct ctl_table *table, int write,
>  }
>  
>  static int sysctl_poolsize = INPUT_POOL_WORDS * 32;
> -extern struct ctl_table random_table[];
> -struct ctl_table random_table[] = {
> +static struct ctl_table random_table[] = {
>  	{
>  		.procname	= "poolsize",
>  		.data		= &sysctl_poolsize,
> @@ -2164,6 +2163,17 @@ struct ctl_table random_table[] = {
>  #endif
>  	{ }
>  };
> +
> +/*
> + * rand_initialize() is called before sysctl_init(),
> + * so we cannot call register_sysctl_init() in rand_initialize()
> + */
> +static int __init random_sysctls_init(void)
> +{
> +	register_sysctl_subdir("kernel", "random", random_table);

No error checking?

:(

[Ocfs2-devel] [PATCH 11/13] random: simplify sysctl declaration with register_sysctl_subdir()

[Xiaoming Ni]

On 2020/5/29 18:26, Greg KH wrote:
> On Fri, May 29, 2020 at 07:41:06AM +0000, Luis Chamberlain wrote:
>> From: Xiaoming Ni <nixiaoming@huawei.com>
>>
>> Move random_table sysctl from kernel/sysctl.c to drivers/char/random.c
>> and use register_sysctl_subdir() to help remove the clutter out of
>> kernel/sysctl.c.
>>
>> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
>> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
>> ---
>>   drivers/char/random.c  | 14 ++++++++++++--
>>   include/linux/sysctl.h |  1 -
>>   kernel/sysctl.c        |  5 -----
>>   3 files changed, 12 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/char/random.c b/drivers/char/random.c
>> index a7cf6aa65908..73fd4b6e9c18 100644
>> --- a/drivers/char/random.c
>> +++ b/drivers/char/random.c
>> @@ -2101,8 +2101,7 @@ static int proc_do_entropy(struct ctl_table *table, int write,
>>   }
>>   
>>   static int sysctl_poolsize = INPUT_POOL_WORDS * 32;
>> -extern struct ctl_table random_table[];
>> -struct ctl_table random_table[] = {
>> +static struct ctl_table random_table[] = {
>>   	{
>>   		.procname	= "poolsize",
>>   		.data		= &sysctl_poolsize,
>> @@ -2164,6 +2163,17 @@ struct ctl_table random_table[] = {
>>   #endif
>>   	{ }
>>   };
>> +
>> +/*
>> + * rand_initialize() is called before sysctl_init(),
>> + * so we cannot call register_sysctl_init() in rand_initialize()
>> + */
>> +static int __init random_sysctls_init(void)
>> +{
>> +	register_sysctl_subdir("kernel", "random", random_table);
> 
> No error checking?
> 
> :(
It was my mistake, I forgot to add a comment here.
Same as the comment of register_sysctl_init(),
There is almost no failure here during the system initialization phase,
and failure in time does not affect the main function.

Thanks
Xiaoming Ni

[Ocfs2-devel] [PATCH 12/13] sysctl: add helper to register empty subdir

[Luis Chamberlain]

The way to create a subdirectory from the base set of directories
is a bit obscure, so provide a helper which makes this clear, and
also helps remove boiler plate code required to do this work.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 include/linux/sysctl.h |  7 +++++++
 kernel/sysctl.c        | 16 +++++++++++++---
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 33a471b56345..89c92390e6de 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -208,6 +208,8 @@ extern void register_sysctl_init(const char *path, struct ctl_table *table,
 extern struct ctl_table_header *register_sysctl_subdir(const char *base,
 						       const char *subdir,
 						       struct ctl_table *table);
+extern void register_sysctl_empty_subdir(const char *base, const char *subdir);
+
 void do_sysctl_args(void);
 
 extern int pwrsw_enabled;
@@ -231,6 +233,11 @@ inline struct ctl_table_header *register_sysctl_subdir(const char *base,
 	return NULL;
 }
 
+static inline void register_sysctl_empty_subdir(const char *base,
+						const char *subdir)
+{
+}
+
 static inline struct ctl_table_header *register_sysctl_paths(
 			const struct ctl_path *path, struct ctl_table *table)
 {
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index f9a35325d5d5..460532cd5ac8 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -3188,13 +3188,17 @@ struct ctl_table_header *register_sysctl_subdir(const char *base,
 		{ }
 	};
 
-	if (!table->procname)
+	if (table != sysctl_mount_point && !table->procname)
 		goto out;
 
 	hdr = register_sysctl_table(base_table);
 	if (unlikely(!hdr)) {
-		pr_err("failed when creating subdirectory sysctl %s/%s/%s\n",
-		       base, subdir, table->procname);
+		if (table != sysctl_mount_point)
+			pr_err("failed when creating subdirectory sysctl %s/%s/%s\n",
+			       base, subdir, table->procname);
+		else
+			pr_err("failed when creating empty subddirectory %s/%s\n",
+			       base, subdir);
 		goto out;
 	}
 	kmemleak_not_leak(hdr);
@@ -3202,6 +3206,12 @@ struct ctl_table_header *register_sysctl_subdir(const char *base,
 	return hdr;
 }
 EXPORT_SYMBOL_GPL(register_sysctl_subdir);
+
+void register_sysctl_empty_subdir(const char *base,
+				  const char *subdir)
+{
+	register_sysctl_subdir(base, subdir, sysctl_mount_point);
+}
 #endif /* CONFIG_SYSCTL */
 /*
  * No sense putting this after each symbol definition, twice,
-- 
2.26.2

[Ocfs2-devel] [PATCH 12/13] sysctl: add helper to register empty subdir

[Kees Cook]

On Fri, May 29, 2020 at 07:41:07AM +0000, Luis Chamberlain wrote:
> The way to create a subdirectory from the base set of directories
> is a bit obscure, so provide a helper which makes this clear, and
> also helps remove boiler plate code required to do this work.
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

[Ocfs2-devel] [PATCH 12/13] sysctl: add helper to register empty subdir

[Eric W. Biederman]

Luis Chamberlain <mcgrof@kernel.org> writes:

> The way to create a subdirectory from the base set of directories
> is a bit obscure, so provide a helper which makes this clear, and
> also helps remove boiler plate code required to do this work.

I agreee calling:
register_sysctl("fs/binfmt_misc", sysctl_mount_point)
is a bit obscure but if you are going to make a wrapper
please make it the trivial one liner above.

Say something that looks like:
	struct sysctl_header *register_sysctl_mount_point(const char *path)
        {
        	return register_sysctl(path, sysctl_mount_point);
        }

And yes please talk about a mount point and not an empty dir, as these
are permanently empty directories to serve as mount points.  There are
some subtle but important permission checks this allows in the case of
unprivileged mounts.

Further code like this belong in proc_sysctl.c next to all of the code
it is related to so that it is easier to see how to refactor the code if
necessary.

Eric

>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  include/linux/sysctl.h |  7 +++++++
>  kernel/sysctl.c        | 16 +++++++++++++---
>  2 files changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
> index 33a471b56345..89c92390e6de 100644
> --- a/include/linux/sysctl.h
> +++ b/include/linux/sysctl.h
> @@ -208,6 +208,8 @@ extern void register_sysctl_init(const char *path, struct ctl_table *table,
>  extern struct ctl_table_header *register_sysctl_subdir(const char *base,
>  						       const char *subdir,
>  						       struct ctl_table *table);
> +extern void register_sysctl_empty_subdir(const char *base, const char *subdir);
> +
>  void do_sysctl_args(void);
>  
>  extern int pwrsw_enabled;
> @@ -231,6 +233,11 @@ inline struct ctl_table_header *register_sysctl_subdir(const char *base,
>  	return NULL;
>  }
>  
> +static inline void register_sysctl_empty_subdir(const char *base,
> +						const char *subdir)
> +{
> +}
> +
>  static inline struct ctl_table_header *register_sysctl_paths(
>  			const struct ctl_path *path, struct ctl_table *table)
>  {
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index f9a35325d5d5..460532cd5ac8 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -3188,13 +3188,17 @@ struct ctl_table_header *register_sysctl_subdir(const char *base,
>  		{ }
>  	};
>  
> -	if (!table->procname)
> +	if (table != sysctl_mount_point && !table->procname)
>  		goto out;
>  
>  	hdr = register_sysctl_table(base_table);
>  	if (unlikely(!hdr)) {
> -		pr_err("failed when creating subdirectory sysctl %s/%s/%s\n",
> -		       base, subdir, table->procname);
> +		if (table != sysctl_mount_point)
> +			pr_err("failed when creating subdirectory sysctl %s/%s/%s\n",
> +			       base, subdir, table->procname);
> +		else
> +			pr_err("failed when creating empty subddirectory %s/%s\n",
> +			       base, subdir);
>  		goto out;
>  	}
>  	kmemleak_not_leak(hdr);
> @@ -3202,6 +3206,12 @@ struct ctl_table_header *register_sysctl_subdir(const char *base,
>  	return hdr;
>  }
>  EXPORT_SYMBOL_GPL(register_sysctl_subdir);
> +
> +void register_sysctl_empty_subdir(const char *base,
> +				  const char *subdir)
> +{
> +	register_sysctl_subdir(base, subdir, sysctl_mount_point);
> +}
>  #endif /* CONFIG_SYSCTL */
>  /*
>   * No sense putting this after each symbol definition, twice,

[Ocfs2-devel] [PATCH 13/13] fs: move binfmt_misc sysctl to its own file

[Luis Chamberlain]

This moves the binfmt_misc sysctl to its own file to help remove
clutter from kernel/sysctl.c.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 fs/binfmt_misc.c | 1 +
 kernel/sysctl.c  | 7 -------
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index f69a043f562b..656b3f5f3bbf 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -821,6 +821,7 @@ static int __init init_misc_binfmt(void)
 	int err = register_filesystem(&bm_fs_type);
 	if (!err)
 		insert_binfmt(&misc_format);
+	register_sysctl_empty_subdir("fs", "binfmt_misc");
 	return err;
 }
 
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 460532cd5ac8..7714e7b476c2 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -3042,13 +3042,6 @@ static struct ctl_table fs_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_TWO,
 	},
-#if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
-	{
-		.procname	= "binfmt_misc",
-		.mode		= 0555,
-		.child		= sysctl_mount_point,
-	},
-#endif
 	{
 		.procname	= "pipe-max-size",
 		.data		= &pipe_max_size,
-- 
2.26.2

[Ocfs2-devel] [PATCH 13/13] fs: move binfmt_misc sysctl to its own file

[Kees Cook]

On Fri, May 29, 2020 at 07:41:08AM +0000, Luis Chamberlain wrote:
> This moves the binfmt_misc sysctl to its own file to help remove
> clutter from kernel/sysctl.c.
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  fs/binfmt_misc.c | 1 +
>  kernel/sysctl.c  | 7 -------
>  2 files changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
> index f69a043f562b..656b3f5f3bbf 100644
> --- a/fs/binfmt_misc.c
> +++ b/fs/binfmt_misc.c
> @@ -821,6 +821,7 @@ static int __init init_misc_binfmt(void)
>  	int err = register_filesystem(&bm_fs_type);
>  	if (!err)
>  		insert_binfmt(&misc_format);
> +	register_sysctl_empty_subdir("fs", "binfmt_misc");
>  	return err;

Nit: let's make the dir before registering the filesystem. I can't
imagine a realistic situation where userspace is reacting so fast it
would actually fail to mount the fs on /proc/sys/fs/binfmt_misc, but why
risk it?

-Kees

>  }
>  
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 460532cd5ac8..7714e7b476c2 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -3042,13 +3042,6 @@ static struct ctl_table fs_table[] = {
>  		.extra1		= SYSCTL_ZERO,
>  		.extra2		= SYSCTL_TWO,
>  	},
> -#if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
> -	{
> -		.procname	= "binfmt_misc",
> -		.mode		= 0555,
> -		.child		= sysctl_mount_point,
> -	},
> -#endif
>  	{
>  		.procname	= "pipe-max-size",
>  		.data		= &pipe_max_size,
> -- 
> 2.26.2
> 

-- 
Kees Cook

[Ocfs2-devel] [PATCH 13/13] fs: move binfmt_misc sysctl to its own file

[Xiaoming Ni]

On 2020/5/29 15:41, Luis Chamberlain wrote:
> This moves the binfmt_misc sysctl to its own file to help remove
> clutter from kernel/sysctl.c.
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>   fs/binfmt_misc.c | 1 +
>   kernel/sysctl.c  | 7 -------
>   2 files changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
> index f69a043f562b..656b3f5f3bbf 100644
> --- a/fs/binfmt_misc.c
> +++ b/fs/binfmt_misc.c
> @@ -821,6 +821,7 @@ static int __init init_misc_binfmt(void)
>   	int err = register_filesystem(&bm_fs_type);
>   	if (!err)
>   		insert_binfmt(&misc_format);
> +	register_sysctl_empty_subdir("fs", "binfmt_misc");
>   	return err;
>   }
build error when CONFIG_BINFMT_MISC=m

ERROR: modpost: "register_sysctl_empty_subdir" [fs/binfmt_misc.ko] 
undefined!

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 27f0c9ea..4129dfb 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2853,6 +2853,7 @@ void register_sysctl_empty_subdir(const char *base,
  {
         register_sysctl_subdir(base, subdir, sysctl_mount_point);
  }
+EXPORT_SYMBOL_GPL(register_sysctl_empty_subdir);
  #endif /* CONFIG_SYSCTL */


Thanks
Xiaoming Ni