On Wed, Feb 19, 2020 at 02:03:50PM +0100, Max Reitz wrote:
> On 11.02.20 17:03, Stefan Hajnoczi wrote:
> > The qcow2 .bdrv_measure() code calculates the crypto payload offset.
> > This logic really belongs in crypto/block.c where it can be reused by
> > other image formats.
> > 
> > The "luks" block driver will need this same logic in order to implement
> > .bdrv_measure(), so extract the qcrypto_block_calculate_payload_offset()
> > function now.
> > 
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  block/qcow2.c          | 74 +++++++++++-------------------------------
> >  crypto/block.c         | 40 +++++++++++++++++++++++
> >  include/crypto/block.h | 22 +++++++++++++
> >  3 files changed, 81 insertions(+), 55 deletions(-)
> 
> [...]
> 
> > diff --git a/crypto/block.c b/crypto/block.c
> > index 325752871c..a9e1b8cc36 100644
> > --- a/crypto/block.c
> > +++ b/crypto/block.c
> > @@ -115,6 +115,46 @@ QCryptoBlock *qcrypto_block_create(QCryptoBlockCreateOptions *options,
> 
> [...]
> 
> > +bool
> > +qcrypto_block_calculate_payload_offset(QCryptoBlockCreateOptions *create_opts,
> > +                                       const char *optprefix,
> > +                                       size_t *len,
> > +                                       Error **errp)
> > +{
> > +    QCryptoBlock *crypto;
> > +    bool ok;
> > +
> > +    /* Fake LUKS creation in order to determine the payload size */
> > +    crypto = qcrypto_block_create(create_opts, optprefix,
> > +                                  qcrypto_block_headerlen_hdr_init_func,
> > +                                  qcrypto_block_headerlen_hdr_write_func,
> > +                                  len, errp);
> > +    ok = crypto != NULL;
> > +    qcrypto_block_free(crypto);
> > +    return ok;
> 
> Speaking of g_autoptr...  Would g_autoptr(QCryptoBlock) crypto; suffice
> to contract these three lines into “return crypto != NULL;”?
> 
> Either way:
> 
> Reviewed-by: Max Reitz <mreitz@redhat.com>

Yes, it can be simplified.  Will fix in v3.

Stefan