From: Mikulas Patocka <mpatocka@redhat.com>
Subject: Re: Desynchronizing dm-raid1
Date: Mon, 12 May 2008 23:28:44 -0400 (EDT)
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To: Herbert Xu <herbert@gondor.apana.org.au>
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On Tue, 6 May 2008, Mikulas Patocka wrote:

> On Tue, 6 May 2008, Herbert Xu wrote:
>
>> Mikulas Patocka <mpatocka@redhat.com> wrote:
>>> 
>>> BTW: is it guaranteed for crypto functions that they read the source data
>>> only once?
>> 
>> There is no such guarantee.
>> 
>> Cheers,
>
> So we'll have to copy the sector to temporary space before encrypting it.
>
> I'll look at it.
>
> Mikulas

Do you think that it would make sense to add a flag to crypto API that 
says that the encryption function reads the input only once? --- so that 
we wouldn't have to copy the data when using an algorithm which doesn't 
need it.

Or do you thint it would be useless (all major disk-encryption algorithms 
read input buffer more times?) or it would create too much code 
complexity?

Mikulas