> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuzn...@redhat.com] > Sent: Wednesday, June 8, 2016 10:19 AM > To: net...@vger.kernel.org > Cc: de...@linuxdriverproject.org; linux-kernel@vger.kernel.org; KY > Srinivasan <k...@microsoft.com>; Haiyang Zhang <haiya...@microsoft.com> > Subject: [PATCH RFC net-next] netvsc: get rid of completion timeouts > > I'm hitting 5 second timeout in rndis_filter_set_rss_param() while setting > RSS parameters for the device. When this happens we end up returning > -ETIMEDOUT from the function and rndis_filter_device_add() falls back to > setting > > net_device->max_chn = 1; > net_device->num_chn = 1; > net_device->num_sc_offered = 0; > > but after a moment the rndis request succeeds and subchannels start to > appear. netvsc_sc_open() does unconditional nvscdev->num_sc_offered-- > and > it becomes U32_MAX-1. Consequent rndis_filter_device_remove() will hang > while waiting for all U32_MAX-1 subchannels to appear and this is not > going to happen. > > The immediate issue could be solved by adding num_sc_offered > 0 check to > netvsc_sc_open() but we're getting out of sync with the host and it's not > easy to adjust things later, e.g. in this particular case we'll be creating > queues without a user request for it and races are expected. Same applies > to other parts of the driver which have the same completion timeout. > > Following the trend in drivers/hv/* code I suggest we remove all these > timeouts completely. As a guest we can always trust the host we're running > on and if the host screws things up there is no easy way to recover anyway. > > Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
Thank you. Acked-by: Haiyang Zhang <haiya...@microsoft.com>
