Re: [PATCH 3/4] crypto: algif_hash - User-space interface for hash operations

[David Miller <davem@davemloft.net>]

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Thu, 04 Nov 2010 12:36:19 -0500

> crypto: algif_hash - User-space interface for hash operations
> 
> This patch adds the af_alg plugin for hash, corresponding to
> the ahash kernel operation type.
> 
> Keys can optionally be set through the setsockopt interface.
> 
> Each sendmsg call will finalise the hash unless sent with a MSG_MORE
> flag.
> 
> Partial hash states can be cloned using accept(2).
> 
> The interface is completely synchronous, all operations will
> complete prior to the system call returning.
> 
> Both sendmsg(2) and splice(2) support reading the user-space
> data directly without copying (except that the Crypto API itself
> may copy the data if alignment is off).
> 
> For now only the splice(2) interface supports performing digest
> instead of init/update/final.  In future the sendmsg(2) interface
> will also be modified to use digest/finup where possible so that
> hardware that cannot return a partial hash state can still benefit
> from this interface.
> 
> Thakns to Miloslav Trmac for reviewing this and contributing
> fixes and improvements.
> 
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Acked-by: David S. Miller <davem@davemloft.net>