Re: [dpdk-dev] [PATCH v3 09/15] net/sfc: use new rte_eth_linkstatus functions

[Stephen Hemminger]

On Tue, 9 Jan 2018 13:35:58 +0300
Andrew Rybchenko <arybche...@solarflare.com> wrote:

> On 01/08/2018 08:45 PM, Stephen Hemminger wrote:
> > Use the new API (_rte_eth_linkstatus_set) to handle link status update.
> >
> > Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
> > ---
> >   drivers/net/sfc/sfc_ethdev.c | 27 +++++++--------------------
> >   drivers/net/sfc/sfc_ev.c     | 23 ++++-------------------
> >   2 files changed, 11 insertions(+), 39 deletions(-)
> >
> > diff --git a/drivers/net/sfc/sfc_ethdev.c b/drivers/net/sfc/sfc_ethdev.c
> > index 2f5f86f84877..e0a12b32b1a3 100644
> > --- a/drivers/net/sfc/sfc_ethdev.c
> > +++ b/drivers/net/sfc/sfc_ethdev.c
> > @@ -238,22 +238,12 @@ static int
> >   sfc_dev_link_update(struct rte_eth_dev *dev, int wait_to_complete)
> >   {
> >     struct sfc_adapter *sa = dev->data->dev_private;
> > -   struct rte_eth_link *dev_link = &dev->data->dev_link;
> > -   struct rte_eth_link old_link;
> >     struct rte_eth_link current_link;
> >   
> >     sfc_log_init(sa, "entry");
> >   
> > -retry:
> > -   EFX_STATIC_ASSERT(sizeof(*dev_link) == sizeof(rte_atomic64_t));
> > -   *(int64_t *)&old_link = rte_atomic64_read((rte_atomic64_t *)dev_link);
> > -
> >     if (sa->state != SFC_ADAPTER_STARTED) {
> >             sfc_port_link_mode_to_info(EFX_LINK_UNKNOWN, &current_link);
> > -           if (!rte_atomic64_cmpset((volatile uint64_t *)dev_link,
> > -                                    *(uint64_t *)&old_link,
> > -                                    *(uint64_t *)&current_link))
> > -                   goto retry;
> >     } else if (wait_to_complete) {
> >             efx_link_mode_t link_mode;
> >   
> > @@ -261,21 +251,18 @@ sfc_dev_link_update(struct rte_eth_dev *dev, int 
> > wait_to_complete)
> >                     link_mode = EFX_LINK_UNKNOWN;
> >             sfc_port_link_mode_to_info(link_mode, &current_link);
> >   
> > -           if (!rte_atomic64_cmpset((volatile uint64_t *)dev_link,
> > -                                    *(uint64_t *)&old_link,
> > -                                    *(uint64_t *)&current_link))
> > -                   goto retry;
> >     } else {
> >             sfc_ev_mgmt_qpoll(sa);
> > -           *(int64_t *)&current_link =
> > -                   rte_atomic64_read((rte_atomic64_t *)dev_link);
> > +           _rte_eth_linkstatus_get(dev, &current_link);
> >     }
> >   
> > -   if (old_link.link_status != current_link.link_status)
> > -           sfc_info(sa, "Link status is %s",
> > -                    current_link.link_status ? "UP" : "DOWN");
> > +   if (_rte_eth_linkstatus_set(dev, &current_link) == 0)
> > +           return 0;
> > +
> > +   sfc_info(sa, "Link status is %s",
> > +            current_link.link_status ? "UP" : "DOWN");
> >   
> > -   return old_link.link_status == current_link.link_status ? 0 : -1;
> > +   return -1;
> >   }
> >   
> >   static void
> > diff --git a/drivers/net/sfc/sfc_ev.c b/drivers/net/sfc/sfc_ev.c
> > index a16dc27b380e..3e96536a9d60 100644
> > --- a/drivers/net/sfc/sfc_ev.c
> > +++ b/drivers/net/sfc/sfc_ev.c
> > @@ -404,29 +404,14 @@ sfc_ev_link_change(void *arg, efx_link_mode_t 
> > link_mode)
> >   {
> >     struct sfc_evq *evq = arg;
> >     struct sfc_adapter *sa = evq->sa;
> > -   struct rte_eth_link *dev_link = &sa->eth_dev->data->dev_link;
> >     struct rte_eth_link new_link;
> > -   uint64_t new_link_u64;
> > -   uint64_t old_link_u64;
> > -
> > -   EFX_STATIC_ASSERT(sizeof(*dev_link) == sizeof(rte_atomic64_t));
> >   
> >     sfc_port_link_mode_to_info(link_mode, &new_link);
> > +   if (_rte_eth_linkstatus_set(sa->eth_dev, &new_link) == 0)
> > +           return B_FALSE;
> >   
> > -   new_link_u64 = *(uint64_t *)&new_link;
> > -   do {
> > -           old_link_u64 = rte_atomic64_read((rte_atomic64_t *)dev_link);
> > -           if (old_link_u64 == new_link_u64)
> > -                   break;
> > -
> > -           if (rte_atomic64_cmpset((volatile uint64_t *)dev_link,
> > -                                   old_link_u64, new_link_u64)) {
> > -                   evq->sa->port.lsc_seq++;
> > -                   break;
> > -           }
> > -   } while (B_TRUE);
> > -
> > -   return B_FALSE;
> > +   evq->sa->port.lsc_seq++;
> > +   return B_TRUE;  
> 
> It still returns B_TRUE, but should return B_FALSE as before.
> Also before the patch lsc_seq is incremented in the case of any
> changes in link status, but now in the case of up/down change only.

The old code looked broken and did not match the comments.
It always returned B_FALSE independent of whether link status changed
or not.