[PATCH] security: selinux: use kmem_cache for ebitmap

[Paul Moore]

On Thu, Jun 8, 2017 at 12:18 AM, Junil Lee <junil0814.lee at lge.com> wrote:
> The allocated size for each ebitmap_node is 192byte by kzalloc().
> Then, ebitmap_node size is fixed, so it's possible to use only 144byte
> for each object by kmem_cache_zalloc().
> It can reduce some dynamic allocation size.
>
> Signed-off-by: Junil Lee <junil0814.lee at lge.com>
> ---
>  security/selinux/ss/ebitmap.c  | 26 ++++++++++++++++++++------
>  security/selinux/ss/ebitmap.h  |  3 +++
>  security/selinux/ss/services.c |  4 ++++
>  3 files changed, 27 insertions(+), 6 deletions(-)

I just applied this to selinux/next, thank you.

> diff --git a/security/selinux/ss/ebitmap.c b/security/selinux/ss/ebitmap.c
> index 9db4709a..ad38299 100644
> --- a/security/selinux/ss/ebitmap.c
> +++ b/security/selinux/ss/ebitmap.c
> @@ -24,6 +24,8 @@
>
>  #define BITS_PER_U64   (sizeof(u64) * 8)
>
> +static struct kmem_cache *ebitmap_node_cachep;
> +
>  int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2)
>  {
>         struct ebitmap_node *n1, *n2;
> @@ -54,7 +56,7 @@ int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src)
>         n = src->node;
>         prev = NULL;
>         while (n) {
> -               new = kzalloc(sizeof(*new), GFP_ATOMIC);
> +               new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
>                 if (!new) {
>                         ebitmap_destroy(dst);
>                         return -ENOMEM;
> @@ -162,7 +164,7 @@ int ebitmap_netlbl_import(struct ebitmap *ebmap,
>                 if (e_iter == NULL ||
>                     offset >= e_iter->startbit + EBITMAP_SIZE) {
>                         e_prev = e_iter;
> -                       e_iter = kzalloc(sizeof(*e_iter), GFP_ATOMIC);
> +                       e_iter = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
>                         if (e_iter == NULL)
>                                 goto netlbl_import_failure;
>                         e_iter->startbit = offset - (offset % EBITMAP_SIZE);
> @@ -288,7 +290,7 @@ int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
>                                         prev->next = n->next;
>                                 else
>                                         e->node = n->next;
> -                               kfree(n);
> +                               kmem_cache_free(ebitmap_node_cachep, n);
>                         }
>                         return 0;
>                 }
> @@ -299,7 +301,7 @@ int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
>         if (!value)
>                 return 0;
>
> -       new = kzalloc(sizeof(*new), GFP_ATOMIC);
> +       new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
>         if (!new)
>                 return -ENOMEM;
>
> @@ -332,7 +334,7 @@ void ebitmap_destroy(struct ebitmap *e)
>         while (n) {
>                 temp = n;
>                 n = n->next;
> -               kfree(temp);
> +               kmem_cache_free(ebitmap_node_cachep, temp);
>         }
>
>         e->highbit = 0;
> @@ -400,7 +402,7 @@ int ebitmap_read(struct ebitmap *e, void *fp)
>
>                 if (!n || startbit >= n->startbit + EBITMAP_SIZE) {
>                         struct ebitmap_node *tmp;
> -                       tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
> +                       tmp = kmem_cache_zalloc(ebitmap_node_cachep, GFP_KERNEL);
>                         if (!tmp) {
>                                 printk(KERN_ERR
>                                        "SELinux: ebitmap: out of memory\n");
> @@ -519,3 +521,15 @@ int ebitmap_write(struct ebitmap *e, void *fp)
>         }
>         return 0;
>  }
> +
> +void ebitmap_cache_init(void)
> +{
> +       ebitmap_node_cachep = kmem_cache_create("ebitmap_node",
> +                                                       sizeof(struct ebitmap_node),
> +                                                       0, SLAB_PANIC, NULL);
> +}
> +
> +void ebitmap_cache_destroy(void)
> +{
> +       kmem_cache_destroy(ebitmap_node_cachep);
> +}
> diff --git a/security/selinux/ss/ebitmap.h b/security/selinux/ss/ebitmap.h
> index 9637b8c..6d5a9ac 100644
> --- a/security/selinux/ss/ebitmap.h
> +++ b/security/selinux/ss/ebitmap.h
> @@ -130,6 +130,9 @@ void ebitmap_destroy(struct ebitmap *e);
>  int ebitmap_read(struct ebitmap *e, void *fp);
>  int ebitmap_write(struct ebitmap *e, void *fp);
>
> +void ebitmap_cache_init(void);
> +void ebitmap_cache_destroy(void);
> +
>  #ifdef CONFIG_NETLABEL
>  int ebitmap_netlbl_export(struct ebitmap *ebmap,
>                           struct netlbl_lsm_catmap **catmap);
> diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
> index 2021666..2f02fa6 100644
> --- a/security/selinux/ss/services.c
> +++ b/security/selinux/ss/services.c
> @@ -2054,9 +2054,11 @@ int security_load_policy(void *data, size_t len)
>
>         if (!ss_initialized) {
>                 avtab_cache_init();
> +               ebitmap_cache_init();
>                 rc = policydb_read(&policydb, fp);
>                 if (rc) {
>                         avtab_cache_destroy();
> +                       ebitmap_cache_destroy();
>                         goto out;
>                 }
>
> @@ -2067,6 +2069,7 @@ int security_load_policy(void *data, size_t len)
>                 if (rc) {
>                         policydb_destroy(&policydb);
>                         avtab_cache_destroy();
> +                       ebitmap_cache_destroy();
>                         goto out;
>                 }
>
> @@ -2074,6 +2077,7 @@ int security_load_policy(void *data, size_t len)
>                 if (rc) {
>                         policydb_destroy(&policydb);
>                         avtab_cache_destroy();
> +                       ebitmap_cache_destroy();
>                         goto out;
>                 }
>
> --
> 2.6.2
>



-- 
paul moore
www.paul-moore.com
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