RE: [EXTERNAL] [PATCH v2 1/2] crypto: fix build issues on unsetting crypto callbacks macro

[Akhil Goyal <gakhil@marvell.com>]

> > > #if may not be needed in application.
> > > Test should be skipped if API is not available/supported.
> > >
> It's needed otherwise application developer has to check the implementation for
> supported/not supported or else
> run the application to get to know whether api is supported or not.
> 

Application is always required to check the return value
or else it will miss the other errors that the API can return.

> > > > diff --git a/lib/cryptodev/rte_cryptodev.c
> > > > b/lib/cryptodev/rte_cryptodev.c index 886eb7a..2e0890f 100644
> > > > --- a/lib/cryptodev/rte_cryptodev.c
> > > > +++ b/lib/cryptodev/rte_cryptodev.c
> > > > @@ -628,6 +628,7 @@
> > rte_cryptodev_asym_xform_capability_check_hash(
> > > >  	return ret;
> > > >  }
> > > >
> > > > +#if RTE_CRYPTO_CALLBACKS
> > > >  /* spinlock for crypto device enq callbacks */  static
> > > > rte_spinlock_t rte_cryptodev_callback_lock =
> > > RTE_SPINLOCK_INITIALIZER;
> > > >
> > > > @@ -744,6 +745,7 @@ cryptodev_cb_init(struct rte_cryptodev *dev)
> > > >  	cryptodev_cb_cleanup(dev);
> > > >  	return -ENOMEM;
> > > >  }
> > > > +#endif /* RTE_CRYPTO_CALLBACKS */
> > >
> > >
> > > > @@ -1485,6 +1491,7 @@ rte_cryptodev_queue_pair_setup(uint8_t
> > dev_id,
> > > > uint16_t queue_pair_id,
> > > >  			socket_id);
> > > >  }
> > > >
> > > > +#if RTE_CRYPTO_CALLBACKS
> > > >  struct rte_cryptodev_cb *
> > > >  rte_cryptodev_add_enq_callback(uint8_t dev_id,
> > > >  			       uint16_t qp_id,
> > > > @@ -1763,6 +1770,7 @@ rte_cryptodev_remove_deq_callback(uint8_t
> > dev_id,
> > > >  	rte_spinlock_unlock(&rte_cryptodev_callback_lock);
> > > >  	return ret;
> > > >  }
> > > > +#endif /* RTE_CRYPTO_CALLBACKS */
> > >
> > > There is an issue here.
> > > The APIs are visible in .h file and are available for application to use.
> > > But the API implementation is compiled out.
> > > Rather, you should add a return ENOTSUP from the beginning of the APIs
> > > if RTE_CRYPTO_CALLBACKS  is enabled.
> > > With this approach application will not need to put #if in its code.
> API declarations wrapped under the macro changes in next patch.

No, that is not the correct way. Application should check the return value.
And we cannot force it to add ifdefs.