From: Ben Hutchings <bhutchings@solarflare•com>
To: Dimitris Michailidis <dm@chelsio•com>
Cc: Alexander Duyck <alexander.h.duyck@intel•com>,
davem@davemloft•net, jeffrey.t.kirsher@intel•com,
netdev@vger•kernel.org
Subject: Re: [ethtool PATCH 4/4] v5 Add RX packet classification interface
Date: Wed, 04 May 2011 00:34:44 +0100 [thread overview]
Message-ID: <1304465684.2873.26.camel@bwh-desktop> (raw)
In-Reply-To: <4DC08E7B.7070906@chelsio.com>
On Tue, 2011-05-03 at 16:23 -0700, Dimitris Michailidis wrote:
> On 05/03/2011 09:12 AM, Alexander Duyck wrote:
[...]
> > +int rxclass_rule_ins(int fd, struct ifreq *ifr,
> > + struct ethtool_rx_flow_spec *fsp)
> > +{
> > + struct ethtool_rxnfc nfccmd;
> > + __u32 loc = fsp->location;
> > + int err;
> > +
> > + /*
> > + * if location is unspecified pull rules from device
> > + * and allocate a free rule for our use
> > + */
> > + if (loc == RX_CLS_LOC_UNSPEC) {
> > + /* init table of available rules */
> > + err = rmgr_init(fd, ifr);
> > + if (err < 0)
> > + return err;
> > +
> > + /* verify rule location */
> > + err = rmgr_add(fsp);
> > + if (err < 0)
> > + return err;
> > +
> > + /* cleanup table and free resources */
> > + rmgr_cleanup();
> > + }
>
> This logic where ethtool tries to select a filter slot when a user provides
> RX_CLS_LOC_UNSPEC does not work in general. It assumes that all slots are
> equal and a new filter can go into any available slot. But a device may have
> restrictions on where a filter may go that ethtool doesn't know.
I agree. And if filter lookup is largely hash-based (as it is in
Solarflare hardware) the user will also find it very difficult to
specify the right location!
> I mentioned during a previous review that for cxgb4 some filters require a
> slot number that is a multiple of 4. There are some other constraints as
> well depending on the type of filter being added. For such a device ethtool
> doesn't know enough to handle RX_CLS_LOC_UNSPEC correctly.
>
> I think RX_CLS_LOC_UNSPEC should be passed to the driver, where there is
> enough knowledge to pick an appropriate slot. So I'd remove the
>
> if (loc == RX_CLS_LOC_UNSPEC)
>
> block above, let the driver pick a slot, and then pass the selected location
> back for ethtool to report.
But first we have to specify this in the ethtool API. So please propose
a patch to ethtool.h.
Ben.
--
Ben Hutchings, Senior Software Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
next prev parent reply other threads:[~2011-05-03 23:34 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-03 16:12 [ethtool PATCH 0/4] Add support for network flow classifier Alexander Duyck
2011-05-03 16:12 ` [ethtool PATCH 1/4] ethtool: remove strings based approach for displaying n-tuple Alexander Duyck
2011-05-03 16:12 ` [ethtool PATCH 2/4] Cleanup defines and header includes to address several issues Alexander Duyck
2011-05-03 16:12 ` [ethtool PATCH 3/4] Add support for __be64 and bitops, centralize several needed macros Alexander Duyck
2011-05-03 16:12 ` [ethtool PATCH 4/4] v5 Add RX packet classification interface Alexander Duyck
2011-05-03 23:23 ` Dimitris Michailidis
2011-05-03 23:34 ` Ben Hutchings [this message]
2011-05-04 0:29 ` Alexander Duyck
2011-05-04 1:35 ` Dimitris Michailidis
2011-05-04 3:10 ` Alexander Duyck
2011-05-04 17:09 ` Dimitris Michailidis
2011-05-04 17:24 ` Ben Hutchings
2011-05-04 17:33 ` Dimitris Michailidis
2011-05-04 17:41 ` Alexander Duyck
2011-05-04 18:05 ` Ben Hutchings
2011-05-04 18:21 ` Alexander Duyck
2011-05-04 18:45 ` Ben Hutchings
2011-05-04 21:07 ` Alexander Duyck
2011-05-04 21:54 ` Ben Hutchings
2011-05-04 19:06 ` Dimitris Michailidis
2011-05-04 18:18 ` Dimitris Michailidis
2011-05-04 18:35 ` Alexander Duyck
2011-05-04 18:50 ` Dimitris Michailidis
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