firmware_loader: move firmware sysctl to its own files

Patch series "sysctl: 3rd set of kernel/sysctl cleanups", v2.

This is the third set of patches to help address cleaning the kitchen
seink in kernel/sysctl.c and to move sysctls away to where they are
actually implemented / used.

This patch (of 8):

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong.  The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

So move the firmware configuration sysctl table to the only place where
it is used, and make it clear that if sysctls are disabled this is not
used.

[[email protected]: export register_firmware_config_sysctl and unregister_firmware_config_sysctl to modules]
[[email protected]: use EXPORT_SYMBOL_NS_GPL instead]
[[email protected]: fix that so it compiles]
  Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: major commit log update to justify the move]

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Xiaoming Ni <[email protected]>
Signed-off-by: Luis Chamberlain <[email protected]>
Signed-off-by: Stephen Rothwell <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Iurii Zaikin <[email protected]>
Cc: Eric Biederman <[email protected]>
Cc: Stephen Kitt <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: "Theodore Ts'o" <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Steven Rostedt (VMware) <[email protected]>
Cc: John Ogness <[email protected]>
Cc: Douglas Gilbert <[email protected]>
Cc: James E.J. Bottomley <[email protected]>
Cc: Martin K. Petersen <[email protected]>
Cc: Lukas Middendorf <[email protected]>
Cc: Antti Palosaari <[email protected]>
Cc: Amir Goldstein <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Benjamin LaHaise <[email protected]>
Cc: Clemens Ladisch <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Cc: Joseph Qi <[email protected]>
Cc: Julia Lawall <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Phillip Potter <[email protected]>
Cc: Qing Wang <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Sebastian Reichel <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Tetsuo Handa <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

5 files changed, 40 insertions, 11 deletions

diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
index d7d63c1aa993..4afb0e9312c0 100644
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -199,11 +199,16 @@ static struct class firmware_class = {
 
 int register_sysfs_loader(void)
 {
-	return class_register(&firmware_class);
+	int ret = class_register(&firmware_class);
+
+	if (ret != 0)
+		return ret;
+	return register_firmware_config_sysctl();
 }
 
 void unregister_sysfs_loader(void)
 {
+	unregister_firmware_config_sysctl();
 	class_unregister(&firmware_class);
 }
 
diff --git a/drivers/base/firmware_loader/fallback.h b/drivers/base/firmware_loader/fallback.h
index 3af7205b302f..9f3055d3b4ca 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..e5ac098d0742 100644
--- a/drivers/base/firmware_loader/fallback_table.c
+++ b/drivers/base/firmware_loader/fallback_table.c
@@ -4,6 +4,7 @@
 #include <linux/kconfig.h>
 #include <linux/list.h>
 #include <linux/slab.h>
+#include <linux/export.h>
 #include <linux/security.h>
 #include <linux/highmem.h>
 #include <linux/umh.h>
@@ -24,7 +25,7 @@ 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 +46,24 @@ struct ctl_table firmware_config_table[] = {
 	},
 	{ }
 };
-#endif
+
+static struct ctl_table_header *firmware_config_sysct_table_header;
+int register_firmware_config_sysctl(void)
+{
+	firmware_config_sysct_table_header =
+		register_sysctl("kernel/firmware_config",
+				firmware_config_table);
+	if (!firmware_config_sysct_table_header)
+		return -ENOMEM;
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(register_firmware_config_sysctl, FIRMWARE_LOADER_PRIVATE);
+
+void unregister_firmware_config_sysctl(void)
+{
+	unregister_sysctl_table(firmware_config_sysct_table_header);
+	firmware_config_sysct_table_header = NULL;
+}
+EXPORT_SYMBOL_NS_GPL(unregister_firmware_config_sysctl, FIRMWARE_LOADER_PRIVATE);
+
+#endif /* CONFIG_SYSCTL */
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 6dd0f277f844..3985e9c80155 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -218,7 +218,6 @@ 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[];
 
 #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 09fa72299f18..5fc3ae16e995 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2154,13 +2154,6 @@ 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,