RE: [PATCH 0/5] Remove CRYPTO_ALG_ALLOCATES_MEMORY flag

[Meenakshi Aggarwal]

Hi Eric, Herbert,

I think Giovanni should send the patch with suggested changes.

Please share your thoughts.

Thanks,
Meenakshi

> -----Original Message-----
> From: Giovanni Cabiddu <giovanni.cabiddu@xxxxxxxxx>
> Sent: Saturday, June 10, 2023 2:11 PM
> To: Eric Biggers <ebiggers@xxxxxxxxxx>; Herbert Xu
> <herbert@xxxxxxxxxxxxxxxxxxx>
> Cc: Meenakshi Aggarwal <meenakshi.aggarwal@xxxxxxx>; Horia Geanta
> <horia.geanta@xxxxxxx>; Varun Sethi <V.Sethi@xxxxxxx>; Pankaj Gupta
> <pankaj.gupta@xxxxxxx>; Gaurav Jain <gaurav.jain@xxxxxxx>;
> davem@xxxxxxxxxxxxx; linux-crypto@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Iuliana Prodan <iuliana.prodan@xxxxxxx>;
> lucas.segarra.fernandez@xxxxxxxxx
> Subject: Re: [PATCH 0/5] Remove CRYPTO_ALG_ALLOCATES_MEMORY flag
> 
> On Fri, Jun 09, 2023 at 05:24:04PM +0800, Herbert Xu wrote:
> > On Thu, Jun 01, 2023 at 12:23:58PM +0100, Giovanni Cabiddu wrote:
> > > BTW, some time ago we did an assessment of the users of
> > > !CRYPTO_ALG_ALLOCATES_MEMORY and we came to the conclusion that
> we
> > > cannot just update the documentation.
> > > dm-crypt uses scatterlists with at most 4 entries. dm-integrity,
> > > instead, might allocate memory for scatterlists with an arbitrary
> > > number of entries.
> >
> > dm-integrity shouldn't be using ALLOCATES_MEMORY at all.  It's using
> > GFP_KERNEL allocations right next to the crypto operations.
> If you all agree, I can send a patch to remove
> CRYPTO_ALG_ALLOCATES_MEMORY from dm-integrity and update the
> documentation in crypto.h.
> 
> > But those are some seriously big crypto operations, 16 thousand 4K
> > pages in one hit?
> 
> Regards,
> 
> --
> Giovanni