On Thu, Aug 20, 2020 at 11:23 PM Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote: > > On 8/20/20 10:42 AM, Krishna Chaitanya wrote: > > On Thu, Aug 20, 2020 at 11:11 PM Krishna Chaitanya > > <chaitanya.mgit@xxxxxxxxx> wrote: > >> > >> On Thu, Aug 20, 2020 at 10:38 PM Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote: > >>> > >>> On 8/20/20 10:00 AM, Krishna Chaitanya wrote: > >>>> On Thu, Aug 20, 2020 at 10:02 PM Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote: > >>>>> > >>>>> On 8/20/20 9:08 AM, Krishna Chaitanya wrote: > >>>>>> On Thu, Aug 20, 2020 at 8:07 PM Wen Gong <wgong@xxxxxxxxxxxxxx> wrote: > >>>>>>> > >>>>>>> On 2020-08-20 18:52, Krishna Chaitanya wrote: > >>>>>>>> On Thu, Aug 20, 2020 at 3:45 PM Wen Gong <wgong@xxxxxxxxxxxxxx> wrote: > >>>>>>>>> > >>>>>>>>> On 2020-08-20 17:19, Krishna Chaitanya wrote: > >>>>>>> ... > >>>>>>>>>>> I'm not really convinced that this is the right fix, but I'm no NAPI > >>>>>>>>>>> expert. Can anyone else help? > >>>>>>>>>> Calling napi_disable() twice can lead to hangs, but moving NAPI from > >>>>>>>>>> start/stop to > >>>>>>>>>> the probe isn't the right approach as the datapath is tied to > >>>>>>>>>> start/stop. > >>>>>>>>>> > >>>>>>>>>> Maybe check the state of NAPI before disable? > >>>>>>>>>> > >>>>>>>>>> if (test_bit(NAPI_STATE_SCHED, &ar->napi.napi.state)) > >>>>>>>>>> napi_disable(&ar->napi) > >>>>>>>>>> or maintain napi_state like this > >>>>>>>>>> https://patchwork.kernel.org/patch/10249365/ > >>>>>>>>> it is better to use above link's patch. > >>>>>>>>> napi.state is controlled by napi API, it is better ath10k not know it. > >>>>>>>> Sure, but IMHO just canceling the async rx work should solve the issue. > >>>>>>> Oh no, canceling the async rx work will not solve this issue, rx worker > >>>>>>> ath10k_rx_indication_async_work call napi_schedule, after napi_complete, > >>>>>>> the NAPI_STATE_SCHED will clear. > >>>>>>> The issue of this patch is because 2 thread called to hif_stop and > >>>>>>> NAPI_STATE_SCHED not clear. > >>>>>> That fix is still valid and good to have. > >>>>>> > >>>>>> ndev_stop being called twice is typical scenarios (stop vs rmmod), so > >>>>>> just checking the netdev_flags for IFF_UP and returning from hif_Stop > >>>>>> should suffice, no? > >>>>> > >>>>> My approach to fix this problem was to add a boolean in ath10k as to whether > >>>>> it had napi enabled or not, and then check that before trying to enable/disable > >>>>> it again. Seems to work fine, and cleaner in my mind than checking internal > >>>>> napi flags. > >>>> A much simpler approach is just to check for IFF_UP and skip NAPI (and others) > >>>> in the hif_stop no? (provided proper RTNL locking is done if hif_stop > >>>> is being called > >>>> internally as well). > >>>> > >>> > >>> I'm not sure, but I think the driver should be internally consistent and not > >>> spend a lot of time trying to guess about interactions with objects higher > >>> in the stack. > >> Fair enough, the network interface state is a basic thing controlled > >> by the driver, > >> so, should be okay to use. Anyways, the in-driver approach has more control. > >>> > >>> Here is my original patch to fix this, it is not complex. > >>> > >>> https://patchwork.kernel.org/patch/10249363/ > >> Sure, I have shared your patch above :). > > Sent a bit early, any idea why this wasn't upstreamed earlier? > > No, one comment from Michal indicated maybe there were more problems lurking > in this area, but he seemed to be OK with the patch over all. After that, > it was just ignored. > Now might be a good time to push for it :)
