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Date: Sat, 7 Apr 2018 13:23:00 +0300
From: Alexey Dobriyan <adobriyan@gmail.com>
Subject: Re: slab_ksize() and friends size_t -> unsigned int?
Message-ID: <20180407102300.GA2083@avx2>
References: <CAGXu5j+Ljf03iYAZY9A2YURJVB_0WvpyhDZHf1Sw_Fec-AfpOw@mail.gmail.com>
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Sender: owner-linux-mm@kvack.org
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To: Kees Cook <keescook@chromium.org>
Cc: Linux-MM <linux-mm@kvack.org>

On Fri, Apr 06, 2018 at 10:06:31PM -0700, Kees Cook wrote:
> I saw all the other int and size_t conversions to unsigned int. What
> about ksize(), slab_ksize() and related functions too? It looks like
> many callers are already expecting unsigned int anyway...
> 
> net/core/skbuff.c:      unsigned int size = frag_size ? : ksize(data);
> 
> Though some are "int", ew:
> 
> int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
>                      gfp_t gfp_mask)
> {
>         int i, osize = skb_end_offset(skb);
>         int size = osize + nhead + ntail;
> ...
>         size = SKB_WITH_OVERHEAD(ksize(data));

slab_ksize() can be changed.
As for ksize(). That path through page allocator is scary.

SLAB can be made unsigned int as well.