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-rw-r--r--include/linux/moduleparam.h56
1 files changed, 56 insertions, 0 deletions
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 6d48831fe7d2..ca74a3402d63 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -130,6 +130,62 @@ __check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
#define module_param(name, type, perm) \
module_param_named(name, name, type, perm)
+/**
+ * kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
+ * @name: the name of the parameter
+ *
+ * There's no point blocking write on a paramter that isn't writable via sysfs!
+ */
+#define kparam_block_sysfs_write(name) \
+ do { \
+ BUG_ON(!(__param_##name.perm & 0222)); \
+ __kernel_param_lock(); \
+ } while (0)
+
+/**
+ * kparam_unblock_sysfs_write - allows sysfs to write to a parameter again.
+ * @name: the name of the parameter
+ */
+#define kparam_unblock_sysfs_write(name) \
+ do { \
+ BUG_ON(!(__param_##name.perm & 0222)); \
+ __kernel_param_unlock(); \
+ } while (0)
+
+/**
+ * kparam_block_sysfs_read - make sure a parameter isn't read via sysfs.
+ * @name: the name of the parameter
+ *
+ * This also blocks sysfs writes.
+ */
+#define kparam_block_sysfs_read(name) \
+ do { \
+ BUG_ON(!(__param_##name.perm & 0444)); \
+ __kernel_param_lock(); \
+ } while (0)
+
+/**
+ * kparam_unblock_sysfs_read - allows sysfs to read a parameter again.
+ * @name: the name of the parameter
+ */
+#define kparam_unblock_sysfs_read(name) \
+ do { \
+ BUG_ON(!(__param_##name.perm & 0444)); \
+ __kernel_param_unlock(); \
+ } while (0)
+
+#ifdef CONFIG_SYSFS
+extern void __kernel_param_lock(void);
+extern void __kernel_param_unlock(void);
+#else
+static inline void __kernel_param_lock(void)
+{
+}
+static inline void __kernel_param_unlock(void)
+{
+}
+#endif
+
#ifndef MODULE
/**
* core_param - define a historical core kernel parameter.