Re: [dpdk-dev] [PATCH v2 1/3] virtio: conditional compilation cleanup

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

On Mon, Jul 04, 2016 at 04:42:32PM +0800, Yuanhan Liu wrote:
> On Mon, Jul 04, 2016 at 02:06:27PM +0530, Jerin Jacob wrote:
> > On Mon, Jul 04, 2016 at 03:36:48PM +0800, Yuanhan Liu wrote:
> > > On Fri, Jul 01, 2016 at 04:46:36PM +0530, Jerin Jacob wrote:
> > > > @@ -494,9 +486,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > >  {
> > > >  	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
> > > >  
> > > > -#ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > -	struct virtio_hw *hw = dev->data->dev_private;
> > > > -#endif
> > > >  	struct virtnet_tx *txvq;
> > > >  	struct virtqueue *vq;
> > > >  	uint16_t tx_free_thresh;
> > > > @@ -511,13 +500,14 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > > >  	}
> > > >  
> > > >  #ifdef RTE_MACHINE_CPUFLAG_SSSE3
> > > > +	struct virtio_hw *hw = dev->data->dev_private;
> > > 
> > > I'd suggest to move above declaration to ...
> > > 
> > > >  	/* Use simple rx/tx func if single segment and no offloads */
> > > >  	if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS &&
> > > >  	     !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> > > 
> > > here: we should try to avoid declaring vars in the middle of a code block.
> > 
> > Next patch in this series, moving all rxtx handler selection code to
> > separate function(virtio_update_rxtx_handler()) where declaration comes
> > as first line in the function.i.e the comment is taken care of in the
> > series.
> 
> Yes, I saw that. But in principle, each patch is atomic: it's not a
> good idea/practice to introduce issues in path A and then fix it in
> path B.

In my view it was not an issue as I was removing all possible
conditional compilation flag. If I were to move the declaration to top
then another conditional compilation RTE_MACHINE_CPUFLAG_SSSE3
flag I need to add around declaring the variable.

Hope this justifies the reason. If you are not convinced then let me know,
if will add the change in next revision.

Jerin

> 
> 	--yliu