From: Cryolitia PukNgae <cryolitia@uniontech.com>

- int param_array_set(const char *val, const struct kernel_param *kp);
- int param_array_get(char *buffer, const struct kernel_param *kp);
- void param_array_free(void *arg);

It would be helpful for the new module param we designed in
snd_usb_audio, in order to run additional custom codes when params
are set in runtime, and re-use the extisted codes in param.c

Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>
---
 include/linux/moduleparam.h | 3 +++
 kernel/params.c             | 9 ++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 3a25122d83e2802e6e6a1475a52816251498b26a..4ef09ad2004789855bd21783029c653fac94b9dd 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -593,6 +593,9 @@ enum hwparam_type {
 
 
 extern const struct kernel_param_ops param_array_ops;
+extern int param_array_set(const char *val, const struct kernel_param *kp);
+extern int param_array_get(char *buffer, const struct kernel_param *kp);
+extern void param_array_free(void *arg);
 
 extern const struct kernel_param_ops param_ops_string;
 extern int param_set_copystring(const char *val, const struct kernel_param *);
diff --git a/kernel/params.c b/kernel/params.c
index b96cfd693c9968012d42acb85611fee1acd47790..a936e018a1c6d0bf2b6b4566f80751840366f652 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -462,7 +462,7 @@ static int param_array(struct module *mod,
 	return 0;
 }
 
-static int param_array_set(const char *val, const struct kernel_param *kp)
+int param_array_set(const char *val, const struct kernel_param *kp)
 {
 	const struct kparam_array *arr = kp->arr;
 	unsigned int temp_num;
@@ -471,8 +471,9 @@ static int param_array_set(const char *val, const struct kernel_param *kp)
 			   arr->elemsize, arr->ops->set, kp->level,
 			   arr->num ?: &temp_num);
 }
+EXPORT_SYMBOL(param_array_set);
 
-static int param_array_get(char *buffer, const struct kernel_param *kp)
+int param_array_get(char *buffer, const struct kernel_param *kp)
 {
 	int i, off, ret;
 	const struct kparam_array *arr = kp->arr;
@@ -492,8 +493,9 @@ static int param_array_get(char *buffer, const struct kernel_param *kp)
 	buffer[off] = '\0';
 	return off;
 }
+EXPORT_SYMBOL(param_array_get);
 
-static void param_array_free(void *arg)
+void param_array_free(void *arg)
 {
 	unsigned int i;
 	const struct kparam_array *arr = arg;
@@ -502,6 +504,7 @@ static void param_array_free(void *arg)
 		for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 			arr->ops->free(arr->elem + arr->elemsize * i);
 }
+EXPORT_SYMBOL(param_array_free);
 
 const struct kernel_param_ops param_array_ops = {
 	.set = param_array_set,

-- 
2.51.0

On Thu, 18 Sep 2025 11:24:31 +0200,
Cryolitia PukNgae via B4 Relay wrote:
> 
> From: Cryolitia PukNgae <cryolitia@uniontech.com>
> 
> - int param_array_set(const char *val, const struct kernel_param *kp);
> - int param_array_get(char *buffer, const struct kernel_param *kp);
> - void param_array_free(void *arg);
> 
> It would be helpful for the new module param we designed in
> snd_usb_audio, in order to run additional custom codes when params
> are set in runtime, and re-use the extisted codes in param.c
> 
> Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>

Can we do just like below?

static int param_set_quirkp(const char *val, const struct kernel_param *kp)
{
	guard(mutex)(&quirk_flags_mutex);
	return param_set_charp(val, kp);
}

static const struct kernel_param_ops param_ops_quirkp = {
	.set = param_set_quirkp,
	.get = param_get_charp,
	.free = param_free_charp,
};
#define param_check_quirkp param_check_charp

modules_param_parray(quirk_flags, quirkp, NULL, 0644);

Then mutex is locked at each time a parameter is set.
Optionally, the string value can be verified in param_set_quirkp()
before passing to param_set_charp(), too.


thanks,

Takashi