From: Phil Sutter <phil@nwl.cc>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netfilter-devel@vger.kernel.org
Subject: Re: [iptables PATCH] nft: Use ARRAY_SIZE() macro in nft_strerror()
Date: Wed, 23 Oct 2019 14:16:27 +0200 [thread overview]
Message-ID: <20191023121627.GM26123@orbyte.nwl.cc> (raw)
In-Reply-To: <20191023112311.qrglbzhqad4vfqvo@salvia>
Hi Pablo,
On Wed, Oct 23, 2019 at 01:23:11PM +0200, Pablo Neira Ayuso wrote:
> On Wed, Oct 23, 2019 at 01:20:24PM +0200, Pablo Neira Ayuso wrote:
> > On Fri, Oct 18, 2019 at 05:51:14PM +0200, Phil Sutter wrote:
> > > Variable 'table' is an array of type struct table_struct, so this is a
> > > classical use-case for ARRAY_SIZE() macro.
> > >
> > > Signed-off-by: Phil Sutter <phil@nwl.cc>
> >
> > Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
>
> BTW, probably good to add the array check?
>
> https://sourceforge.net/p/libhx/libhx/ci/master/tree/include/libHX/defs.h#l152
Copying from kernel sources, do you think that's fine?
| # ifndef ARRAY_SIZE
| -# define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
| +# define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:(-!!(e)); }))
| +# define __same_type(a, b) \
| + __builtin_types_compatible_p(typeof(a), typeof(b))
| +/* &a[0] degrades to a pointer: a different type from an array */
| +# define __must_be_array(a) \
| + BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
| +# define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x))) + __must_be_array(x)
| # endif
Cheers, Phil
next prev parent reply other threads:[~2019-10-23 12:16 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-18 15:51 [iptables PATCH] nft: Use ARRAY_SIZE() macro in nft_strerror() Phil Sutter
2019-10-23 11:20 ` Pablo Neira Ayuso
2019-10-23 11:23 ` Pablo Neira Ayuso
2019-10-23 12:16 ` Phil Sutter [this message]
2019-10-23 20:41 ` Pablo Neira Ayuso
2019-10-24 8:45 ` Phil Sutter
2019-10-24 9:29 ` Pablo Neira Ayuso
2019-10-24 9:51 ` Phil Sutter
2019-10-24 10:01 ` Pablo Neira Ayuso
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