Static keys can now be a module parameter, e.g.
module_param_named(foo, foo.key, static_key_t, 0644)
bcachefs is now using this.
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Petr Pavlu <petr.pavlu@xxxxxxxx>
Cc: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Cc: Daniel Gomez <da.gomez@xxxxxxxxxxx>
Cc: linux-modules@xxxxxxxxxxxxxxx
Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
---
include/linux/jump_label.h | 2 ++
include/linux/moduleparam.h | 6 ++++++
kernel/params.c | 35 +++++++++++++++++++++++++++++++++++
3 files changed, 43 insertions(+)
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index fdb79dd1ebd8..0fc9b71db56f 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -107,6 +107,8 @@ struct static_key {
#endif /* CONFIG_JUMP_LABEL */
};
+typedef struct static_key static_key_t;
+
#endif /* __ASSEMBLY__ */
#ifdef CONFIG_JUMP_LABEL
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index bfb85fd13e1f..2494e7e67453 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -488,6 +488,12 @@ extern int param_set_bint(const char *val, const struct kernel_param *kp);
#define param_get_bint param_get_int
#define param_check_bint param_check_int
+/* A static key, which can only be set like a bool */
+extern const struct kernel_param_ops param_ops_static_key_t;
+extern int param_set_static_key_t(const char *val, const struct kernel_param *kp);
+extern int param_get_static_key_t(char *buffer, const struct kernel_param *kp);
+#define param_check_static_key_t(name, p) __param_check(name, p, struct static_key)
+
/**
* module_param_array - a parameter which is an array of some type
* @name: the name of the array variable
diff --git a/kernel/params.c b/kernel/params.c
index 2509f216c9f3..991f49e138e7 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -14,6 +14,7 @@
#include <linux/overflow.h>
#include <linux/security.h>
#include <linux/slab.h>
+#include <linux/static_key.h>
#include <linux/string.h>
#ifdef CONFIG_SYSFS
@@ -412,6 +413,40 @@ const struct kernel_param_ops param_ops_bint = {
};
EXPORT_SYMBOL(param_ops_bint);
+int param_set_static_key_t(const char *val, const struct kernel_param *kp)
+{
+ /* Match bool exactly, by re-using it. */
+ struct kernel_param boolkp = *kp;
+ bool v;
+ int ret;
+
+ boolkp.arg = &v;
+
+ ret = param_set_bool(val, &boolkp);
+ if (ret)
+ return ret;
+ if (v)
+ static_key_enable(kp->arg);
+ else
+ static_key_disable(kp->arg);
+ return 0;
+}
+EXPORT_SYMBOL(param_set_static_key_t);
+
+int param_get_static_key_t(char *buffer, const struct kernel_param *kp)
+{
+ struct static_key *key = kp->arg;
+ return sprintf(buffer, "%c\n", static_key_enabled(key) ? 'N' : 'Y');
+}
+EXPORT_SYMBOL(param_get_static_key_t);
+
+const struct kernel_param_ops param_ops_static_key_t = {
+ .flags = KERNEL_PARAM_OPS_FL_NOARG,
+ .set = param_set_static_key_t,
+ .get = param_get_static_key_t,
+};
+EXPORT_SYMBOL(param_ops_static_key_t);
+
/* We break the rule and mangle the string. */
static int param_array(struct module *mod,
const char *name,
--
2.49.0
