kernel/params.c: generalize bool_enable_only

[karo-tx-linux.git] / kernel / params.c

diff --git a/kernel/params.c b/kernel/params.c
index a22d6a759b1a9391d5713364097bcfca35f197e7..324624ed620f64460f7532764291026625a90892 100644 (file)
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -251,7 +251,7 @@ char *parse_args(const char *doing,
                return scnprintf(buffer, PAGE_SIZE, format,             \
                                *((type *)kp->arg));                    \
        }                                                               \
-       struct kernel_param_ops param_ops_##name = {                    \
+       const struct kernel_param_ops param_ops_##name = {                      \
                .set = param_set_##name,                                \
                .get = param_get_##name,                                \
        };                                                              \
@@ -303,7 +303,7 @@ static void param_free_charp(void *arg)
        maybe_kfree_parameter(*((char **)arg));
 }
 
-struct kernel_param_ops param_ops_charp = {
+const struct kernel_param_ops param_ops_charp = {
        .set = param_set_charp,
        .get = param_get_charp,
        .free = param_free_charp,
@@ -328,13 +328,43 @@ int param_get_bool(char *buffer, const struct kernel_param *kp)
 }
 EXPORT_SYMBOL(param_get_bool);
 
-struct kernel_param_ops param_ops_bool = {
+const struct kernel_param_ops param_ops_bool = {
        .flags = KERNEL_PARAM_OPS_FL_NOARG,
        .set = param_set_bool,
        .get = param_get_bool,
 };
 EXPORT_SYMBOL(param_ops_bool);
 
+int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
+{
+       int err = 0;
+       bool new_value;
+       bool orig_value = *(bool *)kp->arg;
+       struct kernel_param dummy_kp = *kp;
+
+       dummy_kp.arg = &new_value;
+
+       err = param_set_bool(val, &dummy_kp);
+       if (err)
+               return err;
+
+       /* Don't let them unset it once it's set! */
+       if (!new_value && orig_value)
+               return -EROFS;
+
+       if (new_value)
+               err = param_set_bool(val, kp);
+
+       return err;
+}
+EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
+
+const struct kernel_param_ops param_ops_bool_enable_only = {
+       .flags = KERNEL_PARAM_OPS_FL_NOARG,
+       .set = param_set_bool_enable_only,
+       .get = param_get_bool,
+};
+
 /* This one must be bool. */
 int param_set_invbool(const char *val, const struct kernel_param *kp)
 {
@@ -356,7 +386,7 @@ int param_get_invbool(char *buffer, const struct kernel_param *kp)
 }
 EXPORT_SYMBOL(param_get_invbool);
 
-struct kernel_param_ops param_ops_invbool = {
+const struct kernel_param_ops param_ops_invbool = {
        .set = param_set_invbool,
        .get = param_get_invbool,
 };
@@ -379,7 +409,7 @@ int param_set_bint(const char *val, const struct kernel_param *kp)
 }
 EXPORT_SYMBOL(param_set_bint);
 
-struct kernel_param_ops param_ops_bint = {
+const struct kernel_param_ops param_ops_bint = {
        .flags = KERNEL_PARAM_OPS_FL_NOARG,
        .set = param_set_bint,
        .get = param_get_int,
@@ -476,7 +506,7 @@ static void param_array_free(void *arg)
                        arr->ops->free(arr->elem + arr->elemsize * i);
 }
 
-struct kernel_param_ops param_array_ops = {
+const struct kernel_param_ops param_array_ops = {
        .set = param_array_set,
        .get = param_array_get,
        .free = param_array_free,
@@ -504,7 +534,7 @@ int param_get_string(char *buffer, const struct kernel_param *kp)
 }
 EXPORT_SYMBOL(param_get_string);
 
-struct kernel_param_ops param_ops_string = {
+const struct kernel_param_ops param_ops_string = {
        .set = param_set_copystring,
        .get = param_get_string,
 };