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).
