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authorSteven Rostedt <rostedt@goodmis.org>2013-08-20 15:33:19 +0930
committerRusty Russell <rusty@rustcorp.com.au>2013-08-20 15:37:42 +0930
commitab013c5f60b7ead254863c75b9adc2a47992d01b (patch)
tree9631f1731699398802646d43b170c133c6988fbc
parent7cb14ba75d57910cc4b62115dd5db7bd83c93684 (diff)
downloadlinux-ab013c5f60b7ead254863c75b9adc2a47992d01b.tar.bz2
module: Add flag to allow mod params to have no arguments
Currently the params.c code allows only two "set" functions to have no arguments. If a parameter does not have an argument, then it looks at the set function and tests if it is either param_set_bool() or param_set_bint(). If it is not one of these functions, then it fails the loading of the module. But there may be module parameters that have different set functions and still allow no arguments. But unless each of these cases adds their function to the if statement, it wont be allowed to have no arguments. This method gets rather messing and does not scale. Instead, introduce a flags field to the kernel_param_ops, where if the flag KERNEL_PARAM_FL_NOARG is set, the parameter will not fail if it does not contain an argument. It will be expected that the corresponding set function can handle a NULL pointer as "val". Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--include/linux/moduleparam.h13
-rw-r--r--kernel/params.c6
2 files changed, 16 insertions, 3 deletions
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 27d9da3f86ff..c3eb102a9cc8 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -36,7 +36,18 @@ static const char __UNIQUE_ID(name)[] \
struct kernel_param;
+/*
+ * Flags available for kernel_param_ops
+ *
+ * NOARG - the parameter allows for no argument (foo instead of foo=1)
+ */
+enum {
+ KERNEL_PARAM_FL_NOARG = (1 << 0)
+};
+
struct kernel_param_ops {
+ /* How the ops should behave */
+ unsigned int flags;
/* Returns 0, or -errno. arg is in kp->arg. */
int (*set)(const char *val, const struct kernel_param *kp);
/* Returns length written or -errno. Buffer is 4k (ie. be short!) */
@@ -187,7 +198,7 @@ struct kparam_array
/* Obsolete - use module_param_cb() */
#define module_param_call(name, set, get, arg, perm) \
static struct kernel_param_ops __param_ops_##name = \
- { (void *)set, (void *)get }; \
+ { 0, (void *)set, (void *)get }; \
__module_param_call(MODULE_PARAM_PREFIX, \
name, &__param_ops_##name, arg, \
(perm) + sizeof(__check_old_set_param(set))*0, -1)
diff --git a/kernel/params.c b/kernel/params.c
index 59f7ac7bec04..ec4299cfade8 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -103,8 +103,8 @@ static int parse_one(char *param,
|| params[i].level > max_level)
return 0;
/* No one handled NULL, so do it here. */
- if (!val && params[i].ops->set != param_set_bool
- && params[i].ops->set != param_set_bint)
+ if (!val &&
+ !(params[i].ops->flags & KERNEL_PARAM_FL_NOARG))
return -EINVAL;
pr_debug("handling %s with %p\n", param,
params[i].ops->set);
@@ -320,6 +320,7 @@ int param_get_bool(char *buffer, const struct kernel_param *kp)
EXPORT_SYMBOL(param_get_bool);
struct kernel_param_ops param_ops_bool = {
+ .flags = KERNEL_PARAM_FL_NOARG,
.set = param_set_bool,
.get = param_get_bool,
};
@@ -370,6 +371,7 @@ int param_set_bint(const char *val, const struct kernel_param *kp)
EXPORT_SYMBOL(param_set_bint);
struct kernel_param_ops param_ops_bint = {
+ .flags = KERNEL_PARAM_FL_NOARG,
.set = param_set_bint,
.get = param_get_int,
};