Re: [PATCH 3/6] Protectable Memory

From: Matthew Wilcox <willy@infradead.org>
To: Igor Stoppa <igor.stoppa@huawei.com>
Cc: keescook@chromium.org, mhocko@kernel.org, david@fromorbit.com,
	rppt@linux.vnet.ibm.com, labbott@redhat.com,
	linux-security-module@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	kernel-hardening@lists.openwall.com, igor.stoppa@gmail.com
Subject: Re: [PATCH 3/6] Protectable Memory
Date: Mon, 26 Mar 2018 19:31:10 -0700	[thread overview]
Message-ID: <20180327023110.GD10054@bombadil.infradead.org> (raw)
In-Reply-To: <20180327015524.14318-4-igor.stoppa@huawei.com>

On Tue, Mar 27, 2018 at 04:55:21AM +0300, Igor Stoppa wrote:
> +static inline void *pmalloc_array_align(struct pmalloc_pool *pool,
> +					size_t n, size_t size,
> +					short int align_order)
> +{

You're missing:

        if (size != 0 && n > SIZE_MAX / size)
                return NULL;

> +	return pmalloc_align(pool, n * size, align_order);
> +}

> +static inline void *pcalloc_align(struct pmalloc_pool *pool, size_t n,
> +				  size_t size, short int align_order)
> +{
> +	return pzalloc_align(pool, n * size, align_order);
> +}

Ditto.

> +static inline void *pcalloc(struct pmalloc_pool *pool, size_t n,
> +			    size_t size)
> +{
> +	return pzalloc_align(pool, n * size, PMALLOC_ALIGN_DEFAULT);
> +}

If you make this one:

	return pcalloc_align(pool, n, size, PMALLOC_ALIGN_DEFAULT)

then you don't need the check in this function.

Also, do we really need 'align' as a parameter to the allocator functions
rather than to the pool?

I'd just reuse ARCH_KMALLOC_MINALIGN from slab.h as the alignment, and
then add the special alignment options when we have a real user for them.