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SubjectRe: [patch 1/8] slab: introduce kzfree()
On Mon, Feb 16, 2009 at 03:29:27PM +0100, Johannes Weiner wrote:
> kzfree() is a wrapper for kfree() that additionally zeroes the
> underlying memory before releasing it to the slab allocator.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
> Cc: Matt Mackall <mpm@selenic.com>
> Cc: Christoph Lameter <cl@linux-foundation.org>
> Cc: Nick Piggin <npiggin@suse.de>
> ---
> include/linux/slab.h | 1 +
> mm/util.c | 19 +++++++++++++++++++
> 2 files changed, 20 insertions(+)
>
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -127,6 +127,7 @@ int kmem_ptr_validate(struct kmem_cache
> void * __must_check __krealloc(const void *, size_t, gfp_t);
> void * __must_check krealloc(const void *, size_t, gfp_t);
> void kfree(const void *);
> +void kzfree(const void *);
> size_t ksize(const void *);
>
> /*
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -129,6 +129,25 @@ void *krealloc(const void *p, size_t new
> }
> EXPORT_SYMBOL(krealloc);
>
> +/**
> + * kzfree - like kfree but zero memory
> + * @p: object to free memory of
> + *
> + * The memory of the object @p points to is zeroed before freed.
> + * If @p is %NULL, kzfree() does nothing.
> + */
> +void kzfree(const void *p)
> +{
> + size_t ks;
> + void *mem = (void *)p;
> +
> + if (unlikely(ZERO_OR_NULL_PTR(mem)))
> + return;
> + ks = ksize(mem);
> + memset(mem, 0, ks);
> + kfree(mem);
> +}

Sorry, please fold this delta:

--- a/mm/util.c
+++ b/mm/util.c
@@ -147,6 +147,7 @@ void kzfree(const void *p)
memset(mem, 0, ks);
kfree(mem);
}
+EXPORT_SYMBOL(kzfree);

/*
* strndup_user - duplicate an existing string from user space

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