Re: [PATCH v2] btrfs: LLVMLinux: Remove VLAIS

[Behan Webster]

On 09/11/14 09:34, Chris Mason wrote:
> On 09/05/2014 06:58 PM, behanw@xxxxxxxxxxxxxxxxxx wrote:
> > From: VinÃcius Tinti <viniciustinti@xxxxxxxxx>
> >
> > Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99
> > compliant equivalent. This is the original VLAIS struct.
> >
> > struct {
> > 	struct shash_desc shash;
> > 	char ctx[crypto_shash_descsize(tfm)];
> > } desc;
> >
> > This patch 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.
> We copied this from one of the other crypto api users, and I'm sure
> cooking up all these patches was not a great way to your afternoon.
>
> But, can I talk you into making a helper macro of some kind for this and
> putting it into the crypto api headers?  Honestly this setup seems
> really error prone.
You're not the only person to ask for this. I've got one already coded 
up based on suggestions from tglx.

I've regenerated all the patches. I will resubmit soon.

Will fix.

Behan

--
Behan Webster
behanw@xxxxxxxxxxxxxxxxxx

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