[dm-devel] [PATCH v3 01/12] crypto: LLVMLinux: Add macro to remove use of VLAIS in crypto code

Herbert Xu herbert at gondor.apana.org.au
Wed Sep 17 11:30:35 UTC 2014


On Wed, Sep 17, 2014 at 02:15:40PM +0300, Dmitry Kasatkin wrote:
> On 17/09/14 12:22, Herbert Xu wrote:
> > On Mon, Sep 15, 2014 at 12:30:23AM -0700, behanw at converseincode.com wrote:
> >> From: Behan Webster <behanw at converseincode.com>
> >>
> >> Add a macro which replaces the use of a Variable Length Array In Struct (VLAIS)
> >> with a C99 compliant equivalent. This macro instead allocates the appropriate
> >> amount of memory using an char array.
> >>
> >> The new code can be compiled with both gcc and clang.
> >>
> >> struct shash_desc contains a flexible array member member ctx declared with
> >> CRYPTO_MINALIGN_ATTR, so sizeof(struct shash_desc) aligns the beginning
> >> of the array declared after struct shash_desc with long long.
> >>
> >> No trailing padding is required because it is not a struct type that can
> >> be used in an array.
> >>
> >> The CRYPTO_MINALIGN_ATTR is required so that desc is aligned with long long
> >> as would be the case for a struct containing a member with
> >> CRYPTO_MINALIGN_ATTR.
> >>
> >> Signed-off-by: Behan Webster <behanw at converseincode.com>
> > Acked-by: Herbert Xu <herbert at gondor.apana.org.au>
> >
> > Thanks,
> 
> Just in case.
> I would still follow advice from "Michał Mirosław" to use shash##__desc[]

Oh yes of course.  My ack is more about the approach.

Cheers,
-- 
Email: Herbert Xu <herbert at gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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