[ovs-dev] [RFC v2 PATCH 1/5] dpif-netdev: Refactor dp_netdev_flow_offload_put()

[Sriharsha Basavapatna]

On Tue, May 26, 2020 at 7:12 PM Eli Britstein <elibr at mellanox.com> wrote:
>
>
> On 5/18/2020 10:27 PM, Sriharsha Basavapatna wrote:
> > This patch refactors dp_netdev_flow_offload_put() to prepare for
> > more changes to support partial action offload, in subsequent patches.
> >
> > - Add a wrapper function to allocate flow-mark.
> > - Move netdev_ports_get() to before flow-mark allocation.
> Moving netdev_ports_get position is a change of logic, not just
> refactor. It should be in a separate commit.

I don't want to create 2 commits for this. This is just refactoring,
since 1) it doesn't change the functionality of existing code (we
still allocate a mark if required and we still get a reference to the
in-port's netdev)   2) nor does it change the interface
(inputs/outputs to dp_netdev_flow_offload_put() remain the same) .
But to make it more clear, I'll add additional comments in the commit
log.

Thanks,
-Harsha


> >
> > Signed-off-by: Sriharsha Basavapatna <sriharsha.basavapatna at broadcom.com>
> > ---
> >   lib/dpif-netdev.c | 71 ++++++++++++++++++++++++++++++-----------------
> >   1 file changed, 45 insertions(+), 26 deletions(-)
> >
> > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> > index ea7b187b2..781b233f4 100644
> > --- a/lib/dpif-netdev.c
> > +++ b/lib/dpif-netdev.c
> > @@ -2357,6 +2357,43 @@ dp_netdev_flow_offload_del(struct dp_flow_offload_item *offload)
> >       return mark_to_flow_disassociate(offload->pmd, offload->flow);
> >   }
> >
> > +static int
> > +dp_netdev_alloc_flow_mark(struct dp_netdev_flow *flow, bool modification,
> > +                          uint32_t *markp)
> > +{
> > +    uint32_t mark;
> > +
> > +    if (modification) {
> > +        mark = flow->mark;
> > +        ovs_assert(mark != INVALID_FLOW_MARK);
> > +        *markp = mark;
> > +        return 0;
> > +    }
> > +
> > +    /*
> > +     * If a mega flow has already been offloaded (from other PMD
> > +     * instances), do not offload it again.
> > +     */
> > +    mark = megaflow_to_mark_find(&flow->mega_ufid);
> > +    if (mark != INVALID_FLOW_MARK) {
> > +        VLOG_DBG("Flow has already been offloaded with mark %u\n", mark);
> > +        if (flow->mark != INVALID_FLOW_MARK) {
> > +            ovs_assert(flow->mark == mark);
> > +        } else {
> > +            mark_to_flow_associate(mark, flow);
> > +        }
> > +        return 1;
> > +    }
> > +
> > +    mark = netdev_offload_flow_mark_alloc();
> > +    if (mark == INVALID_FLOW_MARK) {
> > +        VLOG_ERR("Failed to allocate flow mark!\n");
> > +    }
> > +
> > +    *markp = mark;
> > +    return 0;
> > +}
> > +
> >   /*
> >    * There are two flow offload operations here: addition and modification.
> >    *
> > @@ -2385,36 +2422,18 @@ dp_netdev_flow_offload_put(struct dp_flow_offload_item *offload)
> >           return -1;
> >       }
> >
> > -    if (modification) {
> > -        mark = flow->mark;
> > -        ovs_assert(mark != INVALID_FLOW_MARK);
> > -    } else {
> > -        /*
> > -         * If a mega flow has already been offloaded (from other PMD
> > -         * instances), do not offload it again.
> > -         */
> > -        mark = megaflow_to_mark_find(&flow->mega_ufid);
> > -        if (mark != INVALID_FLOW_MARK) {
> > -            VLOG_DBG("Flow has already been offloaded with mark %u\n", mark);
> > -            if (flow->mark != INVALID_FLOW_MARK) {
> > -                ovs_assert(flow->mark == mark);
> > -            } else {
> > -                mark_to_flow_associate(mark, flow);
> > -            }
> > -            return 0;
> > -        }
> > +    port = netdev_ports_get(in_port, dpif_type_str);
> > +    if (!port) {
> > +        return -1;
> > +    }
> >
> > -        mark = netdev_offload_flow_mark_alloc();
> > -        if (mark == INVALID_FLOW_MARK) {
> > -            VLOG_ERR("Failed to allocate flow mark!\n");
> > -        }
> > +    if (dp_netdev_alloc_flow_mark(flow, modification, &mark)) {
> > +            /* flow already offloaded */
> > +            netdev_close(port);
> > +            return 0;
> >       }
> >       info.flow_mark = mark;
> >
> > -    port = netdev_ports_get(in_port, dpif_type_str);
> > -    if (!port) {
> > -        goto err_free;
> > -    }
> >       /* Taking a global 'port_mutex' to fulfill thread safety restrictions for
> >        * the netdev-offload-dpdk module. */
> >       ovs_mutex_lock(&pmd->dp->port_mutex);