Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 29 Mar 2023 13:17:24 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc:     netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        Steve Glendinning <steve.glendinning@shawell.net>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v4] smsc911x: only update stats when interface is up
Message-ID: <20230329131724.4484a881@kernel.org>
In-Reply-To: <ZCSWJxuu1EY/zBFm@shikoro>
References: <20230329064010.24657-1-wsa+renesas@sang-engineering.com>
        <20230329123958.045c9861@kernel.org>
        <ZCSWJxuu1EY/zBFm@shikoro>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Wed, 29 Mar 2023 21:48:55 +0200 Wolfram Sang wrote:
> > Hm, so you opted to not add the flag in the core?
> > To keep the backport small? I think we should just add it..
> > Clearly multiple drivers would benefit and it's not a huge change.  
> 
> I did it this way for two reasons. First, yes, this is a minimal patch
> for backporting. No dependency on core changes, very easy. Second, this
> is a solution I could develop quickly. I am interested in finding
> another solution, but I guess it needs more time, especially as it
> probably touches 15 drivers. I created an action item for it. I hope
> I'll be able to work on it somewhen. But for now, I just need the SMSC
> bug fixed and need to move to the next issue. If we later have the
> generic solution, converting this driver also won't make a lot of a
> difference.

Okay, core changes aside - does pm_runtime_put() imply an RCU sync?
Otherwise your check in get_stats is racy...