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 :).
