From: Matan Azrad <matan@mellanox.com>
To: "Gaëtan Rivet" <gaetan.rivet@6wind.com>
Cc: Adrien Mazarguil <adrien.mazarguil@6wind.com>,
Thomas Monjalon <thomas@monjalon.net>,
"dev@dpdk.org" <dev@dpdk.org>,
"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [PATCH v2 4/4] net/failsafe: fix removed device handling
Date: Thu, 14 Dec 2017 14:43:03 +0000 [thread overview]
Message-ID: <HE1PR0502MB3659BBD4B2681DB8F12516FBD20A0@HE1PR0502MB3659.eurprd05.prod.outlook.com> (raw)
In-Reply-To: <20171214132701.rwlyymuzvrl3tgsu@bidouze.vm.6wind.com>
Hi
> -----Original Message-----
> From: Gaëtan Rivet [mailto:gaetan.rivet@6wind.com]
> Sent: Thursday, December 14, 2017 3:27 PM
> To: Matan Azrad <matan@mellanox.com>
> Cc: Adrien Mazarguil <adrien.mazarguil@6wind.com>; Thomas Monjalon
> <thomas@monjalon.net>; dev@dpdk.org; stable@dpdk.org
> Subject: Re: [PATCH v2 4/4] net/failsafe: fix removed device handling
>
> On Thu, Dec 14, 2017 at 01:07:31PM +0000, Matan Azrad wrote:
> > Hi Gaetan
> >
> > > -----Original Message-----
> > > From: Gaëtan Rivet [mailto:gaetan.rivet@6wind.com]
> > > Sent: Thursday, December 14, 2017 12:49 PM
> > > To: Matan Azrad <matan@mellanox.com>
> > > Cc: Adrien Mazarguil <adrien.mazarguil@6wind.com>; Thomas Monjalon
> > > <thomas@monjalon.net>; dev@dpdk.org; stable@dpdk.org
> > > Subject: Re: [PATCH v2 4/4] net/failsafe: fix removed device
> > > handling
> > >
> > > On Thu, Dec 14, 2017 at 10:40:22AM +0000, Matan Azrad wrote:
> > > > Hi Gaetan
> > > >
> > >
>
> <snip>
>
> > > > > Ok, actually you were right here to do it this way. The "is_removed"
> > > > > check needs to happen after the operation attempt to effectively
> > > > > mitigate the possible race. Checking before attempting the call
> > > > > will be much less effective.
> > > > >
> > > > > That being said, would it be cleaner to have eth_dev ops return
> > > > > -ENODEV directly, and check against it within fail-safe?
> > > > >
> > > >
> > > > I think that according to "is_removed" semantic we must return a
> > > > Boolean
> > > value (Each value different from '0' means that the device is
> > > removed) like other functions in c library (for example isspace()).
> > > >
> > >
> > > Sure, I wasn't discussing the interface proposed by
> > > rte_eth_dev_is_removed().
> > >
> > > What I meant was to ask whether checking rte_eth_dev_is_removed()
> > > would be more interesting in the ethdev layer, making the
> > > eth_dev_ops return -ENODEV regardless of the previous error if this
> > > check is supported by the driver and signal that the port is removed.
> > >
> > > I think this information could be interesting to other systems, not
> > > just fail- safe.
> > >
> >
> > Ok. Got you now.
> > Interesting approach - plan:
> > 1. update fs_link_update to use rte_eth* functions.
>
> I'm surprised it doesn't already.
> Either the rte_eth* function was introduced after the failsafe, or be wary of
> potential issues. I don't see a problem right now though.
>
> > 2. maybe -EIO is preferred because -ENODEV is used for no port
> error?
>
> Good point, didn't think about it.
> Prepare yourself maybe to some arguments about the most relevant error
> code. -EIO seems fine to me, but maybe use a wrapper for all this.
>
> Something like:
>
> ---8<---
>
> static int
> eth_error(pid, int original_ret)
> {
> int ret;
>
> if (original_ret == 0)
> return original_ret;
> ret = rte_eth_is_removed(pid);
> if (ret == 0 || ret == -ENOTSUP)
> return original_ret;
> return -EIO;
> }
>
> int
> rte_eth_ops_xyz(pid)
> {
> int ret;
> ret = eth_dev(pid).ops_xyz();
> return eth_error(pid, ret);
> }
>
> --->8---
>
> This way you would be able to change it easily and the logic would be
> insulated.
>
Nice.
> > 3. update all relevant rte_eth* to use "is_removed" in error flows(1
> patch for flow APIs and 1 for the others).
> > 4. Change fs checks in error flows to check rte_eth* return values.
> > 5. Remove CC stable from commit massage.
> >
> > What do you think?
> >
>
> Agreed otherwise.
>
Will create V3, thanks!
> Thanks,
>
> > > --
> > > Gaëtan Rivet
> > > 6WIND
>
> --
> Gaëtan Rivet
> 6WIND
prev parent reply other threads:[~2017-12-14 14:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1509637324-13525-1-git-send-email-matan@mellanox.com>
2017-11-02 15:42 ` [dpdk-stable] [PATCH 1/3] net/failsafe: fix removal handling lack Matan Azrad
2017-11-06 8:19 ` Gaëtan Rivet
[not found] ` <1513175370-16583-1-git-send-email-matan@mellanox.com>
2017-12-13 14:29 ` [dpdk-stable] [PATCH v2 4/4] net/failsafe: fix removed device handling Matan Azrad
2017-12-13 15:16 ` Gaëtan Rivet
2017-12-13 15:48 ` Matan Azrad
2017-12-13 16:09 ` Gaëtan Rivet
2017-12-13 17:09 ` Thomas Monjalon
2017-12-14 10:40 ` Matan Azrad
2017-12-13 21:55 ` Gaëtan Rivet
2017-12-14 10:40 ` Matan Azrad
2017-12-14 10:48 ` Gaëtan Rivet
2017-12-14 13:07 ` Matan Azrad
2017-12-14 13:27 ` Gaëtan Rivet
2017-12-14 14:43 ` Matan Azrad [this message]
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