LinuxLists.cc - [PATCH] module.h: allow #define strings to work with MODULE_IMPORT

2022-01-08 14:07:05

Subject: [PATCH] module.h: allow #define strings to work with MODULE_IMPORT_NS

The MODULE_IMPORT_NS() macro does not allow defined strings to work
properly with it, so add a layer of indirection to allow this to happen.

Cc: Luis Chamberlain <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Matthias Maennich <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
Note, there is no in-kernel user of this, I wrote this to help deal with
some module namespace issues that Android kernels were having where we
wanted to put the namespace name in a build #define to make things
easier over time when combined with the change at:
https://lore.kernel.org/all/[email protected]/

I can also see this be used in ways to make namespace names up "on the
fly at build time" when combined with the above-referenced change to
create a different namespace for every time the kernel is built to do a
poor-man's symbol mangling to make life harder for out-of-tree modules.
Not that I would ever suggest such a thing :)

include/linux/module.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index c9f1200b2312..f4338235ed2c 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -290,7 +290,8 @@ extern typeof(name) __mod_##type##__##name##_device_table \
* files require multiple MODULE_FIRMWARE() specifiers */
#define MODULE_FIRMWARE(_firmware) MODULE_INFO(firmware, _firmware)

-#define MODULE_IMPORT_NS(ns) MODULE_INFO(import_ns, #ns)
+#define _MODULE_IMPORT_NS(ns) MODULE_INFO(import_ns, #ns)
+#define MODULE_IMPORT_NS(ns) _MODULE_IMPORT_NS(ns)

struct notifier_block;

--
2.34.1

2022-01-10 17:39:41

by Matthias Maennich

[permalink] [raw]

Subject: Re: [PATCH] module.h: allow #define strings to work with MODULE_IMPORT_NS

On Sat, Jan 08, 2022 at 03:06:57PM +0100, Greg Kroah-Hartman wrote:
>The MODULE_IMPORT_NS() macro does not allow defined strings to work
>properly with it, so add a layer of indirection to allow this to happen.
>
>Cc: Luis Chamberlain <[email protected]>
>Cc: Jessica Yu <[email protected]>
>Cc: Matthias Maennich <[email protected]>
>Signed-off-by: Greg Kroah-Hartman <[email protected]>

Reviewed-by: Matthias Maennich <[email protected]>

Cheers,
Matthias

>---
>Note, there is no in-kernel user of this, I wrote this to help deal with
>some module namespace issues that Android kernels were having where we
>wanted to put the namespace name in a build #define to make things
>easier over time when combined with the change at:
> https://lore.kernel.org/all/[email protected]/
>
>I can also see this be used in ways to make namespace names up "on the
>fly at build time" when combined with the above-referenced change to
>create a different namespace for every time the kernel is built to do a
>poor-man's symbol mangling to make life harder for out-of-tree modules.
>Not that I would ever suggest such a thing :)
>
> include/linux/module.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/include/linux/module.h b/include/linux/module.h
>index c9f1200b2312..f4338235ed2c 100644
>--- a/include/linux/module.h
>+++ b/include/linux/module.h
>@@ -290,7 +290,8 @@ extern typeof(name) __mod_##type##__##name##_device_table \
> * files require multiple MODULE_FIRMWARE() specifiers */
> #define MODULE_FIRMWARE(_firmware) MODULE_INFO(firmware, _firmware)
>
>-#define MODULE_IMPORT_NS(ns) MODULE_INFO(import_ns, #ns)
>+#define _MODULE_IMPORT_NS(ns) MODULE_INFO(import_ns, #ns)
>+#define MODULE_IMPORT_NS(ns) _MODULE_IMPORT_NS(ns)
>
> struct notifier_block;
>
>--
>2.34.1
>

2022-01-12 03:13:27

by Luis Chamberlain

[permalink] [raw]