linux-kernel - Re: [PATCH v7] drbd: Convert from ahash to shash

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Date:   Wed, 5 Sep 2018 10:10:24 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Kees Cook <keescook@...omium.org>,
        Philipp Reisner <philipp.reisner@...bit.com>,
        linux-block <linux-block@...r.kernel.org>,
        drbd-dev@...ts.linbit.com, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7] drbd: Convert from ahash to shash

On 9/5/18 10:04 AM, Kees Cook wrote:
> On Wed, Sep 5, 2018 at 1:33 AM, Lars Ellenberg
> <lars.ellenberg@...bit.com> wrote:
>> On Tue, Sep 04, 2018 at 08:04:18PM -0700, Kees Cook wrote:
>>> On Mon, Sep 3, 2018 at 11:04 PM, Kees Cook <keescook@...omium.org> wrote:
>>>> On Mon, Aug 6, 2018 at 4:32 PM, Kees Cook <keescook@...omium.org> wrote:
>>>>> In preparing to remove all stack VLA usage from the kernel[1], this
>>>>> removes the discouraged use of AHASH_REQUEST_ON_STACK in favor of
>>>>> the smaller SHASH_DESC_ON_STACK by converting from ahash-wrapped-shash
>>>>> to direct shash. By removing a layer of indirection this both improves
>>>>> performance and reduces stack usage. The stack allocation will be made
>>>>> a fixed size in a later patch to the crypto subsystem.
>>>>>
>>>>> The bulk of the lines in this change are simple s/ahash/shash/, but the
>>>>> main logic differences are in drbd_csum_ee() and drbd_csum_bio(), which
>>>>> externalizes the page walking with k(un)map_atomic() instead of using
>>>>> scattergather.
>>>>
>>>> Hi Lars! How does this look to you? If you can Ack I assume Jens would
>>>> be able to take this.
>>
>> Sure, I should have ACKed it a month ago already.  As I said, I believe
>> you the crypto. And you added the kmap_atomic as I pointed out.
>> All good.
> 
> Great, thanks! Jens, can you take this?

Done, queued up for 4.20.

-- 
Jens Axboe