module_param: allow 'bool' module_params to be bool, not just int.

Impact: API cleanup

For historical reasons, 'bool' parameters must be an int, not a bool.
But there are around 600 users, so a conversion seems like useless churn.

So we use __same_type() to distinguish, and handle both cases.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 009a5f768768555ca43a73b00a36a5aeea7415cd..6547c3cdbc4c17cddda61d0f92fe83352de2f77c 100644 (file)
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -38,6 +38,7 @@ typedef int (*param_get_fn)(char *buffer, struct kernel_param *kp);
 
 /* Flag bits for kernel_param.flags */
 #define KPARAM_KMALLOCED       1
+#define KPARAM_ISBOOL          2
 
 struct kernel_param {
        const char *name;
@@ -83,7 +84,7 @@ struct kparam_array
    parameters.  perm sets the visibility in sysfs: 000 means it's
    not there, read bits mean it's readable, write bits mean it's
    writable. */
-#define __module_param_call(prefix, name, set, get, arg, perm)         \
+#define __module_param_call(prefix, name, set, get, arg, isbool, perm) \
        /* Default value instead of permissions? */                     \
        static int __param_perm_check_##name __attribute__((unused)) =  \
        BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))  \
@@ -92,10 +93,13 @@ struct kparam_array
        static struct kernel_param __moduleparam_const __param_##name   \
        __used                                                          \
     __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
-       = { __param_str_##name, perm, 0, set, get, { arg } }
+       = { __param_str_##name, perm, isbool ? KPARAM_ISBOOL : 0,       \
+           set, get, { arg } }
 
 #define module_param_call(name, set, get, arg, perm)                         \
-       __module_param_call(MODULE_PARAM_PREFIX, name, set, get, arg, perm)
+       __module_param_call(MODULE_PARAM_PREFIX,                              \
+                           name, set, get, arg,                              \
+                           __same_type(*(arg), bool), perm)
 
 /* Helper functions: type is byte, short, ushort, int, uint, long,
    ulong, charp, bool or invbool, or XXX if you define param_get_XXX,
@@ -124,15 +128,16 @@ struct kparam_array
 #define core_param(name, var, type, perm)                              \
        param_check_##type(name, &(var));                               \
        __module_param_call("", name, param_set_##type, param_get_##type, \
-                           &var, perm)
+                           &var, __same_type(var, bool), perm)
 #endif /* !MODULE */
 
 /* Actually copy string: maxlen param is usually sizeof(string). */
 #define module_param_string(name, string, len, perm)                   \
        static const struct kparam_string __param_string_##name         \
                = { len, string };                                      \
-       module_param_call(name, param_set_copystring, param_get_string, \
-                         .str = &__param_string_##name, perm);         \
+       __module_param_call(MODULE_PARAM_PREFIX, name,                  \
+                           param_set_copystring, param_get_string,     \
+                           .str = &__param_string_##name, 0, perm);    \
        __MODULE_PARM_TYPE(name, "string")
 
 /* Called on module insert or kernel boot */
@@ -190,9 +195,16 @@ extern int param_set_charp(const char *val, struct kernel_param *kp);
 extern int param_get_charp(char *buffer, struct kernel_param *kp);
 #define param_check_charp(name, p) __param_check(name, p, char *)
 
+/* For historical reasons "bool" parameters can be (unsigned) "int". */
 extern int param_set_bool(const char *val, struct kernel_param *kp);
 extern int param_get_bool(char *buffer, struct kernel_param *kp);
-#define param_check_bool(name, p) __param_check(name, p, int)
+#define param_check_bool(name, p)                                      \
+       static inline void __check_##name(void)                         \
+       {                                                               \
+               BUILD_BUG_ON(!__same_type(*(p), bool) &&                \
+                            !__same_type(*(p), unsigned int) &&        \
+                            !__same_type(*(p), int));                  \
+       }
 
 extern int param_set_invbool(const char *val, struct kernel_param *kp);
 extern int param_get_invbool(char *buffer, struct kernel_param *kp);
@@ -203,8 +215,10 @@ extern int param_get_invbool(char *buffer, struct kernel_param *kp);
        static const struct kparam_array __param_arr_##name             \
        = { ARRAY_SIZE(array), nump, param_set_##type, param_get_##type,\
            sizeof(array[0]), array };                                  \
-       module_param_call(name, param_array_set, param_array_get,       \
-                         .arr = &__param_arr_##name, perm);            \
+       __module_param_call(MODULE_PARAM_PREFIX, name,                  \
+                           param_array_set, param_array_get,           \
+                           .arr = &__param_arr_##name,                 \
+                           __same_type(array[0], bool), perm);         \
        __MODULE_PARM_TYPE(name, "array of " #type)
 
 #define module_param_array(name, type, nump, perm)             \

diff --git a/kernel/params.c b/kernel/params.c
index b4660dc13dbcbbe3bfbafc3498fb55b26078be76..7f6912ced2bab2c957da0ef3edc6e70625560837 100644 (file)
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -238,35 +238,54 @@ int param_get_charp(char *buffer, struct kernel_param *kp)
        return sprintf(buffer, "%s", *((char **)kp->arg));
 }
 
+/* Actually could be a bool or an int, for historical reasons. */
 int param_set_bool(const char *val, struct kernel_param *kp)
 {
+       bool v;
+
        /* No equals means "set"... */
        if (!val) val = "1";
 
        /* One of =[yYnN01] */
        switch (val[0]) {
        case 'y': case 'Y': case '1':
-               *(int *)kp->arg = 1;
-               return 0;
+               v = true;
+               break;
        case 'n': case 'N': case '0':
-               *(int *)kp->arg = 0;
-               return 0;
+               v = false;
+               break;
+       default:
+               return -EINVAL;
        }
-       return -EINVAL;
+
+       if (kp->flags & KPARAM_ISBOOL)
+               *(bool *)kp->arg = v;
+       else
+               *(int *)kp->arg = v;
+       return 0;
 }
 
 int param_get_bool(char *buffer, struct kernel_param *kp)
 {
+       bool val;
+       if (kp->flags & KPARAM_ISBOOL)
+               val = *(bool *)kp->arg;
+       else
+               val = *(int *)kp->arg;
+
        /* Y and N chosen as being relatively non-coder friendly */
-       return sprintf(buffer, "%c", (*(int *)kp->arg) ? 'Y' : 'N');
+       return sprintf(buffer, "%c", val ? 'Y' : 'N');
 }
 
+/* This one must be bool. */
 int param_set_invbool(const char *val, struct kernel_param *kp)
 {
-       int boolval, ret;
+       int ret;
+       bool boolval;
        struct kernel_param dummy;
 
        dummy.arg = &boolval;
+       dummy.flags = KPARAM_ISBOOL;
        ret = param_set_bool(val, &dummy);
        if (ret == 0)
                *(bool *)kp->arg = !boolval;