lkml.org 
[lkml]   [2009]   [Feb]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
Subject[PATCH 3/4] module_param: allow 'bool' module_params to be bool, not just (unsigned) int.

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.
Be a little clever about it:

1) Put a size arg in struct kernel_param,
2) Allow int, unsigned int or bool in param_check_bool(),
3) Use the size to know what to do in the set and get functions.

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

diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -38,7 +38,8 @@ typedef int (*param_get_fn)(char *buffer

struct kernel_param {
const char *name;
- unsigned int perm;
+ u16 perm;
+ u16 size;
param_set_fn set;
param_get_fn get;
union {
@@ -79,7 +80,7 @@ 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, asize, perm) \
/* Default value instead of permissions? */ \
static int __param_perm_check_##name __attribute__((unused)) = \
BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \
@@ -88,10 +89,11 @@ struct kparam_array
static struct kernel_param __moduleparam_const __param_##name \
__used \
__attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
- = { __param_str_##name, perm, set, get, { arg } }
+ = { __param_str_##name, perm, asize, 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, sizeof(*(arg)), perm)

/* Helper functions: type is byte, short, ushort, int, uint, long,
ulong, charp, bool or invbool, or XXX if you define param_get_XXX,
@@ -120,15 +122,16 @@ 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, sizeof(var), 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 */
@@ -176,9 +179,14 @@ extern int param_get_charp(char *buffer,
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 "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) \
+ { \
+ (void)(union { int *i; unsigned *u; bool *b; })(p); \
+ }

/* #include <stdbool.h> transforms module_param(foo, bool, 0). */
#define param_set__Bool param_set_bool
@@ -194,8 +202,10 @@ extern int param_get_invbool(char *buffe
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, \
+ sizeof(array[0]), 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
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -226,6 +226,7 @@ int param_get_charp(char *buffer, struct
return sprintf(buffer, "%s", *((char **)kp->arg));
}

+/* Actually could be a bool or an int. */
int param_set_bool(const char *val, struct kernel_param *kp)
{
/* No equals means "set"... */
@@ -234,10 +235,10 @@ int param_set_bool(const char *val, stru
/* One of =[yYnN01] */
switch (val[0]) {
case 'y': case 'Y': case '1':
- *(int *)kp->arg = 1;
+ memset(kp->arg, 0xff, kp->size);
return 0;
case 'n': case 'N': case '0':
- *(int *)kp->arg = 0;
+ memset(kp->arg, 0, kp->size);
return 0;
}
return -EINVAL;
@@ -245,16 +246,25 @@ int param_set_bool(const char *val, stru

int param_get_bool(char *buffer, struct kernel_param *kp)
{
+ bool val;
+ if (sizeof(kp->arg) == sizeof(int))
+ val = *(int *)kp->arg;
+ else
+ val = *(bool *)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.size = sizeof(boolval);
ret = param_set_bool(val, &dummy);
if (ret == 0)
*(bool *)kp->arg = !boolval;


\
 
 \ /
  Last update: 2009-02-09 08:59    [W:3.152 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site