On 2020-08-20 17:19, Krishna Chaitanya wrote:
...
> diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c
> index 7b894dcaad2e..b71499b171c6 100644
> --- a/drivers/net/wireless/ath/ath10k/sdio.c
> +++ b/drivers/net/wireless/ath/ath10k/sdio.c
> @@ -1756,8 +1756,6 @@ static int ath10k_sdio_hif_start(struct ath10k *ar)
> struct ath10k_sdio *ar_sdio = ath10k_sdio_priv(ar);
> int ret;
>
> - napi_enable(&ar->napi);
> -
> /* Sleep 20 ms before HIF interrupts are disabled.
> * This will give target plenty of time to process the BMI done
> * request before interrupts are disabled.
> @@ -1884,7 +1882,6 @@ static void ath10k_sdio_hif_stop(struct ath10k *ar)
> spin_unlock_bh(&ar_sdio->wr_async_lock);
>
> napi_synchronize(&ar->napi);
> - napi_disable(&ar->napi);
> }
>
> #ifdef CONFIG_PM
> @@ -2121,6 +2118,7 @@ static int ath10k_sdio_probe(struct sdio_func *func,
>
> netif_napi_add(&ar->napi_dev, &ar->napi, ath10k_sdio_napi_poll,
> ATH10K_NAPI_BUDGET);
> + napi_enable(&ar->napi);
>
> ath10k_dbg(ar, ATH10K_DBG_BOOT,
> "sdio new func %d vendor 0x%x device 0x%x block 0x%x/0x%x\n",
> @@ -2235,6 +2233,7 @@ static void ath10k_sdio_remove(struct sdio_func *func)
>
> ath10k_core_unregister(ar);
>
> + napi_disable(&ar->napi);
> netif_napi_del(&ar->napi);
>
> ath10k_core_destroy(ar);
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.
Also, the most common cause for such issues (1st
napi_synchronize/napi_disable hang)
is that napi_poll is being scheduled, so, you might want to check that
napi_schedule isn't
called after stop.
cd ath10k; git log --grep=napi shows plenty of such issues. the one
that matches closest is
c2cac2f74ab4bcf0db0dcf3a612f1e5b52d145c8, so, it could just be a
regression.
This above commit's scene is not same with this patch.
It is hang for only do 1 simulate crash of the commit, this patch is
doing simulate crash and rmmod meanwhile.
