Commit 39e0a6bd authored by Greg Kurz's avatar Greg Kurz Committed by Greg Kroah-Hartman

9p/trans_virtio: discard zero-length reply

commit 26d99834 upstream.

When a 9p request is successfully flushed, the server is expected to just
mark it as used without sending a 9p reply (ie, without writing data into
the buffer). In this case, virtqueue_get_buf() will return len == 0 and
we must not report a REQ_STATUS_RCVD status to the client, otherwise the
client will erroneously assume the request has not been flushed.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kurz <groug@kaod.org>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent efb1cbc2
......@@ -160,7 +160,8 @@ static void req_done(struct virtqueue *vq)
spin_unlock_irqrestore(&chan->lock, flags);
/* Wakeup if anyone waiting for VirtIO ring space. */
wake_up(chan->vc_wq);
p9_client_cb(chan->client, req, REQ_STATUS_RCVD);
if (len)
p9_client_cb(chan->client, req, REQ_STATUS_RCVD);
}
}
......
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