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Y . Srinivasan" , Haiyang Zhang , Stephen Hemminger , Wei Liu , linux-hyperv@vger.kernel.org, Michael Kelley , Dexuan Cui , Boqun Feng , Vitaly Kuznetsov , "David S. Miller" , netdev@vger.kernel.org Subject: Re: [RFC PATCH 04/11] hv_netvsc: Disable NAPI before closing the VMBus channel Message-ID: <20200326175531.GA20523@andrea> References: <20200325225505.23998-1-parri.andrea@gmail.com> <20200325225505.23998-5-parri.andrea@gmail.com> <20200326082636.1d777921@hermes.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200326082636.1d777921@hermes.lan> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Mar 26, 2020 at 08:26:36AM -0700, Stephen Hemminger wrote: > On Wed, 25 Mar 2020 23:54:58 +0100 > "Andrea Parri (Microsoft)" wrote: > > > vmbus_chan_sched() might call the netvsc driver callback function that > > ends up scheduling NAPI work. This "work" can access the channel ring > > buffer, so we must ensure that any such work is completed and that the > > ring buffer is no longer being accessed before freeing the ring buffer > > data structure in the channel closure path. To this end, disable NAPI > > before calling vmbus_close() in netvsc_device_remove(). > > > > Suggested-by: Michael Kelley > > Signed-off-by: Andrea Parri (Microsoft) > > Cc: "David S. Miller" > > Cc: > > Do you have a test that reproduces this issue? I don't (or I'm not aware of such a test). > > The netvsc device is somewhat unique in that it needs NAPI > enabled on the primary channel to interact with the host. > Therefore it can't call napi_disable in the normal dev->stop() place. > > Acked-by: Stephen Hemminger Thanks! Andrea