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Commit fddd5201 authored by Rusty Russell's avatar Rusty Russell
Browse files

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: default avatarRusty Russell <rusty@rustcorp.com.au>
parent d2c123c2

include/linux/moduleparam.h

+23 −9
Original line number Diff line number Diff line
@@ -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)		\

kernel/params.c

+26 −7
Original line number Diff line number Diff line
@@ -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;

	}



	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;