Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH net-next v2] netvsc: get rid of completion timeouts | Date | Thu, 09 Jun 2016 10:53:34 +0200 |
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David Miller <davem@davemloft.net> writes:
> From: Vitaly Kuznetsov <vkuznets@redhat.com> > Date: Wed, 8 Jun 2016 19:17:41 +0200 > >> 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 <vkuznets@redhat.com> >> Acked-by: Haiyang Zhang <haiyangz@microsoft.com> > > This doesn't apply cleanly to net-next, I get rejects.
Sorry for the screw up, apparently I forgot about my own cleanups I sent before. v3 is coming.
-- Vitaly
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