Re: [PATCH 1/4] block: use ARCH_KMALLOC_MINALIGN as the default dma pad mask

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, May 21, 2008 at 06:34:45PM +0900, FUJITA Tomonori wrote:
>
> Why do crypto need to know exactly the minimum alignment guaranteed by
> kmalloc? Can you tell me an example how the alignment breaks crypto?

It's used to make the context aligned so that for most algorithms
we can get to the context without going through ALIGN_PTR.  Only
algorithms requiring alignments bigger than that offered by kmalloc
would have to use ALIGN_PTR.  This is important because the context
is used on the fast path, i.e., for AES every block has to access
the context.

If we used an alignment value is bigger than that guaranteed by
kmalloc then this would break because the context may end up
unaligned.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Linux IIO]     [Samba]     [Device Mapper]
  Powered by Linux