From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Jessica Yu <jeyu@kernel.org>,
        Matthias Maennich <maennich@google.com>
Subject: [PATCH] module.h: allow #define strings to work with MODULE_IMPORT_NS
Date:   Sat,  8 Jan 2022 15:06:57 +0100
Message-Id: <20220108140657.3361237-1-gregkh@linuxfoundation.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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 <mcgrof@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Matthias Maennich <maennich@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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/20220108140415.3360088-1-gregkh@linuxfoundation.org/

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