svn commit: r258328 - head/sys/net

[Robert Watson]

On Wed, 20 Nov 2013, Julian Elischer wrote:

>> After that it'd be nice to write a set of mbuf list macros for abstract the 
>> whole queue, dequeue, concat, iterate, etc (like sys/queue.h, but for 
>> mbufs.)
>> 
>> What do people think?
>> 
>> (I've been doing it for m->next chained things, but not m->m_nextpkt 
>> things..)
>
> I was thinking: new interfaces.. (your -multi names sound good). macros for 
> handling said lists so that people don't screw them up Old drivers run with 
> no change.

To me, the name "multi" is ambiguous: could be multicast.  If we call the new 
datastructure "mbqueue" or "mqueue", then we should name the method 
ether_input_mbqueue or ether_input_mqueue.

Robert




>
>> 
>> 
>> 
>> -adrian
>> 
>> 
>> On 18 November 2013 14:58, George V. Neville-Neil <gnn at freebsd.org> wrote:
>>> Author: gnn
>>> Date: Mon Nov 18 22:58:14 2013
>>> New Revision: 258328
>>> URL: http://svnweb.freebsd.org/changeset/base/258328
>>> 
>>> Log:
>>>    Allow ethernet drivers to pass in packets connected via the nextpkt 
>>> pointer.
>>>    Handling packets in this way allows drivers to amortize work during 
>>> packet reception.
>>>
>>>    Submitted by: Vijay Singh
>>>    Sponsored by: NetApp
>>> 
>>> Modified:
>>>    head/sys/net/if_ethersubr.c
>>> 
>>> Modified: head/sys/net/if_ethersubr.c
>>> ==============================================================================
>>> --- head/sys/net/if_ethersubr.c Mon Nov 18 22:55:50 2013        (r258327)
>>> +++ head/sys/net/if_ethersubr.c Mon Nov 18 22:58:14 2013        (r258328)
>>> @@ -708,13 +708,25 @@ static void
>>>   ether_input(struct ifnet *ifp, struct mbuf *m)
>>>   {
>>> 
>>> +       struct mbuf *mn;
>>> +
>>>          /*
>>> -        * We will rely on rcvif being set properly in the deferred 
>>> context,
>>> -        * so assert it is correct here.
>>> +        * The drivers are allowed to pass in a chain of packets linked 
>>> with
>>> +        * m_nextpkt. We split them up into separate packets here and pass
>>> +        * them up. This allows the drivers to amortize the receive lock.
>>>           */
>>> -       KASSERT(m->m_pkthdr.rcvif == ifp, ("%s: ifnet mismatch", 
>>> __func__));
>>> +       while (m) {
>>> +               mn = m->m_nextpkt;
>>> +               m->m_nextpkt = NULL;
>>> 
>>> -       netisr_dispatch(NETISR_ETHER, m);
>>> +               /*
>>> +                * We will rely on rcvif being set properly in the 
>>> deferred context,
>>> +                * so assert it is correct here.
>>> +                */
>>> +               KASSERT(m->m_pkthdr.rcvif == ifp, ("%s: ifnet mismatch", 
>>> __func__));
>>> +               netisr_dispatch(NETISR_ETHER, m);
>>> +               m = mn;
>>> +       }
>>>   }
>>>
>>>   /*
>
>