lkml.org 
[lkml]   [2016]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH net-next v3] netvsc: get rid of completion timeouts
    From
    From: Vitaly Kuznetsov <vkuznets@redhat.com>
    Date: Thu, 9 Jun 2016 12:44:03 +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>

    Applied.

    \
     
     \ /
      Last update: 2016-06-09 21:21    [W:2.202 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site