Re: [PATCH RESEND] mm: Restructure kmem_cache_create() to move debugcache integrity checks into a new function

From: JoonSoo Kim
Date: Mon Aug 06 2012 - 12:49:19 EST


> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 12637ce..08bc2a4 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -23,6 +23,41 @@ enum slab_state slab_state;
> LIST_HEAD(slab_caches);
> DEFINE_MUTEX(slab_mutex);
>
> +static int kmem_cache_sanity_check(const char *name, size_t size)
> +{
> +#ifdef CONFIG_DEBUG_VM
> + struct kmem_cache *s = NULL;
> +
> + list_for_each_entry(s, &slab_caches, list) {
> + char tmp;
> + int res;
> +
> + /*
> + * This happens when the module gets unloaded and doesn't
> + * destroy its slab cache and no-one else reuses the vmalloc
> + * area of the module. Print a warning.
> + */
> + res = probe_kernel_address(s->name, tmp);
> + if (res) {
> + pr_err("Slab cache with size %d has lost its name\n",
> + s->object_size);
> + continue;
> + }
> +
> + if (!strcmp(s->name, name)) {
> + pr_err("%s (%s): Cache name already exists.\n",
> + __func__, name);
> + dump_stack();
> + s = NULL;
> + return -EINVAL;
> + }
> + }
> +
> + WARN_ON(strchr(name, ' ')); /* It confuses parsers */
> +#endif
> + return 0;
> +}

As I know, following is more preferable than above.

#ifdef CONFIG_DEBUG_VM
static int kmem_cache_sanity_check(const char *name, size_t size);
#else
static inline int kmem_cache_sanity_check(const char *name, size_t size)
{
return 0;
}
#endif

Is there any reason to do like that?
Thanks.
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