lkml.org 
[lkml]   [2016]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH net-next v2] netvsc: get rid of completion timeouts
Date
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

\
 
 \ /
  Last update: 2016-06-09 11:41    [W:0.180 / U:0.520 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site