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From: Leon Romanovsky <leon@kernel.org>
To: Jakub Kicinski <kuba@kernel.org>
Cc: "David S . Miller" <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH net-next v1] netdevsim: Forbid devlink reload when adding or deleting ports
Date: Fri, 6 Aug 2021 14:19:43 +0300	[thread overview]
Message-ID: <YQ0az49ARwITkbHW@unreal> (raw)
In-Reply-To: <20210805121203.1ac615d4@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>

On Thu, Aug 05, 2021 at 12:12:03PM -0700, Jakub Kicinski wrote:
> On Thu, 5 Aug 2021 21:02:23 +0300 Leon Romanovsky wrote:
> > > > As it should, given add/delete ports takes the port_list_lock which is
> > > > destroyed by down but not (due to the forced failure) re-initialized by
> > > > up.
> > > > 
> > > > If we want to handle adding ports while down we can just bump port
> > > > count and return, although I don't think there's a practical need
> > > > to support that.  
> > > 
> > > Sorry, but for me netdevsim looks like complete dumpster. 
> 
> I worry that netdevsim's gone unwieldy as a reflection of the quality of
> the devlink APIs that got added, not by itself :/
> 
> > > It was intended for fast prototyping, but ended to be huge pile of
> > > debugfs entries and selftest to execute random flows.
> 
> It's for selftests, IDK what fast prototyping is in terms of driver
> APIs. Fast prototyping makes me think of the "it works" attitude which
> is not sufficiently high bar for core APIs IMO, I'm sure you'll agree.
> 
> netdevsim was written specifically to be able to exercise HW APIs which
> are implemented by small fraction of drivers. Especially offload APIs
> as those can easily be broken by people changing the SW implementation
> without capable HW at hand.
> 
> BTW I wonder if there is a term in human science of situation like when
> a recent contributor tells the guy who wrote the code what the code was
> intended for :)

"Teaching grandmother to suck eggs" ? :)

> 
> > > Do you want me to move in_reload = false line to be after if (nsim_dev->fail_reload)
> > > check?  
> > 
> > BTW, the current implementation where in_reload before if, actually
> > preserves same behaviour as was with devlink_reload_enable() implementation.
> 
> Right, but I think as you rightly pointed out the current protection
> of reload is broken. I'm not saying you must make it perfect or else..
> just pointing out a gap you could address if you so choose.

I don't know, netdevsim needs some dedicated cleanup.

Thanks

      reply	other threads:[~2021-08-06 11:19 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-05 11:02 [PATCH net-next] " Leon Romanovsky
2021-08-05 11:05 ` [PATCH net-next v1] " Leon Romanovsky
2021-08-05 12:40 ` [PATCH net-next] " patchwork-bot+netdevbpf
2021-08-05 13:15 ` [PATCH net-next v1] " Jakub Kicinski
2021-08-05 13:51   ` Leon Romanovsky
2021-08-05 14:23     ` Jakub Kicinski
2021-08-05 14:33       ` Leon Romanovsky
2021-08-05 15:27         ` Jakub Kicinski
2021-08-05 17:35           ` Leon Romanovsky
2021-08-05 18:02             ` Leon Romanovsky
2021-08-05 19:12               ` Jakub Kicinski
2021-08-06 11:19                 ` Leon Romanovsky [this message]

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