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SubjectRe: [PATCH] kref: remove kref_set
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On Tue, 2010-03-16 at 15:14 +1100, NeilBrown wrote:
>
> Of the three uses of kref_set in the kernel:
>
> One really should be kref_put as the code is letting go of a
> reference,
> Two really should be kref_init because the kref is being
> initialised.
>
> This suggests that making kref_set available encourages bad code.
> So fix the three uses and remove kref_set completely.
>
> Signed-off-by: NeilBrown <neilb@suse.de>

Tested the IMA section. Looks good.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>

Thanks!

Mimi
> --
>
> The two 'kref_init' calls in ima_iint.c could equally be a single
> call after the kmem_cache_alloc in ima_inode_alloc, but this version
> was the minimal code change.
>
>
> diff --git a/include/linux/kref.h b/include/linux/kref.h
> index b0cb0eb..13003ee 100644
> --- a/include/linux/kref.h
> +++ b/include/linux/kref.h
> @@ -21,7 +21,6 @@ struct kref {
> atomic_t refcount;
> };
>
> -void kref_set(struct kref *kref, int num);
> void kref_init(struct kref *kref);
> void kref_get(struct kref *kref);
> int kref_put(struct kref *kref, void (*release) (struct kref *kref));
> diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
> index 076c7c8..b2d70d3 100644
> --- a/kernel/user_namespace.c
> +++ b/kernel/user_namespace.c
> @@ -54,8 +54,8 @@ int create_user_ns(struct cred *new)
> #endif
> /* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */
>
> - /* alloc_uid() incremented the userns refcount. Just set it to 1 */
> - kref_set(&ns->kref, 1);
> + /* root_user holds a reference to ns, our reference can be dropped */
> + put_user_ns(ns);
>
> return 0;
> }
> diff --git a/lib/kref.c b/lib/kref.c
> index 9ecd6e8..69761d3 100644
> --- a/lib/kref.c
> +++ b/lib/kref.c
> @@ -15,23 +15,13 @@
> #include <linux/module.h>
>
> /**
> - * kref_set - initialize object and set refcount to requested number.
> - * @kref: object in question.
> - * @num: initial reference counter
> - */
> -void kref_set(struct kref *kref, int num)
> -{
> - atomic_set(&kref->refcount, num);
> - smp_mb();
> -}
> -
> -/**
> * kref_init - initialize object.
> * @kref: object in question.
> */
> void kref_init(struct kref *kref)
> {
> - kref_set(kref, 1);
> + atomic_set(&kref->refcount, 1);
> + smp_mb();
> }
>
> /**
> @@ -71,7 +61,6 @@ int kref_put(struct kref *kref, void (*release)(struct kref *kref))
> return 0;
> }
>
> -EXPORT_SYMBOL(kref_set);
> EXPORT_SYMBOL(kref_init);
> EXPORT_SYMBOL(kref_get);
> EXPORT_SYMBOL(kref_put);
> diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c
> index 2d4d05d..91c31d8 100644
> --- a/security/integrity/ima/ima_iint.c
> +++ b/security/integrity/ima/ima_iint.c
> @@ -93,7 +93,7 @@ void iint_free(struct kref *kref)
> iint->opencount);
> iint->opencount = 0;
> }
> - kref_set(&iint->refcount, 1);
> + kref_init(&iint->refcount);
> kmem_cache_free(iint_cache, iint);
> }
>
> @@ -132,7 +132,7 @@ static void init_once(void *foo)
> iint->readcount = 0;
> iint->writecount = 0;
> iint->opencount = 0;
> - kref_set(&iint->refcount, 1);
> + kref_init(&iint->refcount);
> }
>
> static int __init ima_iintcache_init(void)




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