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    SubjectRe: [RFC PATCH 04/11] hv_netvsc: Disable NAPI before closing the VMBus channel
    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)" <parri.andrea@gmail.com> 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 <mikelley@microsoft.com>
    > > Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
    > > Cc: "David S. Miller" <davem@davemloft.net>
    > > Cc: <netdev@vger.kernel.org>
    >
    > 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 <stephen@networkplumber.org>

    Thanks!

    Andrea

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