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Commit 45fcc70c authored by Rusty Russell's avatar Rusty Russell
Browse files

module_param: split perm field into flags and perm 



Impact: cleanup

Rather than hack KPARAM_KMALLOCED into the perm field, separate it out.
Since the perm field was 32 bits and only needs 16, we don't add bloat.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 9a71af2c

include/linux/moduleparam.h

+6 −2
Original line number Diff line number Diff line
@@ -36,9 +36,13 @@ typedef int (*param_set_fn)(const char *val, struct kernel_param *kp); 
/* Returns length written or -errno.  Buffer is 4k (ie. be short!) */

typedef int (*param_get_fn)(char *buffer, struct kernel_param *kp);



/* Flag bits for kernel_param.flags */

#define KPARAM_KMALLOCED	1



struct kernel_param {

	const char *name;

	unsigned int perm;

	u16 perm;

	u16 flags;

	param_set_fn set;

	param_get_fn get;

	union {
@@ -88,7 +92,7 @@ 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, 0, set, get, { arg } }



#define module_param_call(name, set, get, arg, perm)			      \

	__module_param_call(MODULE_PARAM_PREFIX, name, set, get, arg, perm)

kernel/params.c

+3 −6
Original line number Diff line number Diff line
@@ -24,9 +24,6 @@ 
#include <linux/err.h>

#include <linux/slab.h>



/* We abuse the high bits of "perm" to record whether we kmalloc'ed. */

#define KPARAM_KMALLOCED	0x80000000



#if 0

#define DEBUGP printk

#else
@@ -220,13 +217,13 @@ int param_set_charp(const char *val, struct kernel_param *kp) 
		return -ENOSPC;

	}



	if (kp->perm & KPARAM_KMALLOCED)

	if (kp->flags & KPARAM_KMALLOCED)

		kfree(*(char **)kp->arg);



	/* This is a hack.  We can't need to strdup in early boot, and we

	 * don't need to; this mangled commandline is preserved. */

	if (slab_is_available()) {

		kp->perm |= KPARAM_KMALLOCED;

		kp->flags |= KPARAM_KMALLOCED;

		*(char **)kp->arg = kstrdup(val, GFP_KERNEL);

		if (!kp->arg)

			return -ENOMEM;
@@ -591,7 +588,7 @@ void destroy_params(const struct kernel_param *params, unsigned num) 
	unsigned int i;



	for (i = 0; i < num; i++)

		if (params[i].perm & KPARAM_KMALLOCED)

		if (params[i].flags & KPARAM_KMALLOCED)

			kfree(*(char **)params[i].arg);

}