From: Jakub Kicinski <kuba@kernel.org>
To: Leon Romanovsky <leon@kernel.org>
Cc: Ivan Vecera <ivecera@redhat.com>,
SlawomirX Laba <slawomirx.laba@intel.com>,
Eric Dumazet <edumazet@google.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"Piotrowski, Patryk" <patryk.piotrowski@intel.com>,
Paolo Abeni <pabeni@redhat.com>,
"moderated list:INTEL ETHERNET DRIVERS\"
<intel-wired-lan@lists.osuosl.org>,
open list <linux-kernel@vger.kernel.org>"@osuosl.org,
"David S. Miller" <davem@davemloft.net>,
"sassmann@redhat.com" <sassmann@redhat.com>
Subject: Re: [Intel-wired-lan] [PATCH net] iavf: Do not restart Tx queues after reset task failure
Date: Thu, 10 Nov 2022 12:24:18 -0800 [thread overview]
Message-ID: <20221110122418.32414666@kernel.org> (raw)
In-Reply-To: <Y20vtqd6raqg8iwy@unreal>
On Thu, 10 Nov 2022 19:07:02 +0200 Leon Romanovsky wrote:
> > > Yes I think you're right. A ton of people check it without the
> > > lock but I think thats not strictly safe. Is dev_close safe to
> > > call when netif_running is false? Why not just remove the check
> > > and always call dev_close then.
> >
> > Check for a bit value (like netif_runnning()) is much cheaper than
> > unconditionally taking global lock like RTNL.
>
> This cheap operation is racy and performed in non-performance
> critical path.
To be clear - the rtnl_lock around the entire if is still racy
in the grand scheme of things, no? What's stopping someone from
bringing the device right back up after you drop the lock?
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next prev parent reply other threads:[~2022-11-10 22:29 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-08 10:25 [Intel-wired-lan] [PATCH net] iavf: Do not restart Tx queues after reset task failure Ivan Vecera
2022-11-08 16:40 ` Jacob Keller
2022-11-09 18:20 ` Leon Romanovsky
2022-11-09 20:11 ` Keller, Jacob E
2022-11-10 9:17 ` Leon Romanovsky
2022-11-10 14:51 ` Ivan Vecera
2022-11-10 17:07 ` Leon Romanovsky
2022-11-10 20:24 ` Jakub Kicinski [this message]
2022-11-10 21:07 ` Leon Romanovsky
2022-11-10 21:13 ` Keller, Jacob E
2022-11-18 14:30 ` Jankowski, Konrad0
2022-11-18 14:31 ` Jankowski, Konrad0
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